Make aura work with mus

ui/aura/mus/window_tree_client.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "services/ui/public/cpp/window_tree_client.h"
+#include "ui/aura/mus/window_tree_client.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
 #include <vector>
 
+#include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/memory/ptr_util.h"
 #include "services/service_manager/public/cpp/connector.h"
-#include "services/ui/common/util.h"
-#include "services/ui/public/cpp/in_flight_change.h"
-#include "services/ui/public/cpp/input_event_handler.h"
-#include "services/ui/public/cpp/surface_id_handler.h"
-#include "services/ui/public/cpp/window_drop_target.h"
-#include "services/ui/public/cpp/window_manager_delegate.h"
-#include "services/ui/public/cpp/window_observer.h"
-#include "services/ui/public/cpp/window_private.h"
-#include "services/ui/public/cpp/window_tracker.h"
-#include "services/ui/public/cpp/window_tree_client_delegate.h"
-#include "services/ui/public/cpp/window_tree_client_observer.h"
 #include "services/ui/public/interfaces/window_manager_window_tree_factory.mojom.h"
+#include "ui/aura/client/aura_constants.h"
+#include "ui/aura/client/capture_client.h"
+#include "ui/aura/client/focus_client.h"
+#include "ui/aura/mus/in_flight_change.h"
+#include "ui/aura/mus/input_method_mus.h"
+#include "ui/aura/mus/property_converter.h"
+#include "ui/aura/mus/surface_id_handler.h"
+#include "ui/aura/mus/window_manager_delegate.h"
+#include "ui/aura/mus/window_mus.h"
+#include "ui/aura/mus/window_port_mus.h"
+#include "ui/aura/mus/window_tree_client_delegate.h"
+#include "ui/aura/mus/window_tree_client_observer.h"
+#include "ui/aura/mus/window_tree_host_mus.h"
+#include "ui/aura/window.h"
+#include "ui/aura/window_delegate.h"
+#include "ui/aura/window_tracker.h"
 #include "ui/events/event.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
 
-namespace ui {
+#if defined(HiWord)
+#undef HiWord
+#endif
+#if defined(LoWord)
+#undef LoWord
+#endif
+
+namespace aura {
+namespace {
 
 Id MakeTransportId(ClientSpecificId client_id, ClientSpecificId local_id) {
   return (client_id << 16) | local_id;
 }
 
-// Helper called to construct a local window object from transport data.
-Window* AddWindowToClient(WindowTreeClient* client,
-                          Window* parent,
-                          const mojom::WindowDataPtr& window_data) {
-  // We don't use the ctor that takes a WindowTreeClient here, since it will
-  // call back to the service and attempt to create a new window.
-  Window* window = WindowPrivate::LocalCreate();
-  WindowPrivate private_window(window);
-  private_window.set_client(client);
-  private_window.set_server_id(window_data->window_id);
-  private_window.set_visible(window_data->visible);
-  private_window.set_properties(
-      window_data->properties
-          .To<std::map<std::string, std::vector<uint8_t>>>());
-  client->AddWindow(window);
-  private_window.LocalSetBounds(gfx::Rect(), window_data->bounds);
-  if (parent)
-    WindowPrivate(parent).LocalAddChild(window);
-  return window;
+bool ShouldCreateTopLevel(ui::wm::WindowType type) {
+  switch (type) {
+    case ui::wm::WINDOW_TYPE_CONTROL:
+    case ui::wm::WINDOW_TYPE_UNKNOWN:
+      return false;
+
+    case ui::wm::WINDOW_TYPE_NORMAL:
+    case ui::wm::WINDOW_TYPE_POPUP:
+    case ui::wm::WINDOW_TYPE_PANEL:
+    case ui::wm::WINDOW_TYPE_MENU:
+    case ui::wm::WINDOW_TYPE_TOOLTIP:
+      break;
+  }
+  return true;
 }
 
+inline uint16_t HiWord(uint32_t id) {
+  return static_cast<uint16_t>((id >> 16) & 0xFFFF);
+}
+
+inline uint16_t LoWord(uint32_t id) {
+  return static_cast<uint16_t>(id & 0xFFFF);
+}
+
+struct WindowPortPropertyDataMus : public WindowPortPropertyData {
+  std::string transport_name;
+  std::unique_ptr<std::vector<uint8_t>> transport_value;
+};
+
+// Handles acknowledgment of an input event, either immediately when a nested
+// message loop starts, or upon destruction.
+class EventAckHandler : public base::MessageLoop::NestingObserver {
+ public:
+  explicit EventAckHandler(std::unique_ptr<EventResultCallback> ack_callback)
+      : ack_callback_(std::move(ack_callback)) {
+    DCHECK(ack_callback_);
+    base::MessageLoop::current()->AddNestingObserver(this);
+  }
+
+  ~EventAckHandler() override {
+    base::MessageLoop::current()->RemoveNestingObserver(this);
+    if (ack_callback_) {
+      ack_callback_->Run(handled_ ? ui::mojom::EventResult::HANDLED
+                                  : ui::mojom::EventResult::UNHANDLED);
+    }
+  }
+
+  void set_handled(bool handled) { handled_ = handled; }
+
+  // base::MessageLoop::NestingObserver:
+  void OnBeginNestedMessageLoop() override {
+    // Acknowledge the event immediately if a nested message loop starts.
+    // Otherwise we appear unresponsive for the life of the nested message loop.
+    if (ack_callback_) {
+      ack_callback_->Run(ui::mojom::EventResult::HANDLED);
+      ack_callback_.reset();
+    }
+  }
+
+ private:
+  std::unique_ptr<EventResultCallback> ack_callback_;
+  bool handled_ = false;
+
+  DISALLOW_COPY_AND_ASSIGN(EventAckHandler);
+};
+
+}  // namespace
+
 struct WindowTreeClient::CurrentDragState {
   // The current change id of the current drag an drop ipc.
   uint32_t change_id;
 
   // The effect to return when we send our finish signal.
   uint32_t completed_action;
 
   // Callback executed when a drag initiated by PerformDragDrop() is completed.
   base::Callback<void(bool, uint32_t)> on_finished;
 };
 
 WindowTreeClient::WindowTreeClient(
     WindowTreeClientDelegate* delegate,
     WindowManagerDelegate* window_manager_delegate,
-    mojo::InterfaceRequest<mojom::WindowTreeClient> request)
+    mojo::InterfaceRequest<ui::mojom::WindowTreeClient> request)
     : client_id_(0),
       next_window_id_(1),
       next_change_id_(1),
       delegate_(delegate),
       window_manager_delegate_(window_manager_delegate),
-      capture_window_(nullptr),
-      focused_window_(nullptr),
       binding_(this),
       tree_(nullptr),
       in_destructor_(false),
       weak_factory_(this) {
   // Allow for a null request in tests.
   if (request.is_pending())
     binding_.Bind(std::move(request));
+  delegate_->GetFocusClient()->AddObserver(this);
+  delegate_->GetCaptureClient()->AddObserver(this);
   if (window_manager_delegate)
     window_manager_delegate->SetWindowManagerClient(this);
 }
 
 WindowTreeClient::~WindowTreeClient() {
   in_destructor_ = true;
 
-  for (auto& observer : observers_)
+  for (WindowTreeClientObserver& observer : observers_)
     observer.OnWillDestroyClient(this);
 
   std::vector<Window*> non_owned;
   WindowTracker tracker;
   while (!windows_.empty()) {
     IdToWindowMap::iterator it = windows_.begin();
-    if (it->second->WasCreatedByThisClient()) {
-      it->second->Destroy();
+    if (WasCreatedByThisClient(it->second)) {
+      const Id window_id = it->second->server_id();
+      delete it->second->GetWindow();
+      DCHECK_EQ(0u, windows_.count(window_id));
     } else {
-      tracker.Add(it->second);
+      tracker.Add(it->second->GetWindow());
       windows_.erase(it);
     }
   }
 
   // Delete the non-owned windows last. In the typical case these are roots. The
   // exception is the window manager and embed roots, which may know about
   // other random windows that it doesn't own.
-  // NOTE: we manually delete as we're a friend.
   while (!tracker.windows().empty())
     delete tracker.windows().front();
 
-  for (auto& observer : observers_)
+  for (WindowTreeClientObserver& observer : observers_)
     observer.OnDidDestroyClient(this);
+
+  delegate_->GetFocusClient()->RemoveObserver(this);
+  delegate_->GetCaptureClient()->RemoveObserver(this);
 }
 
 void WindowTreeClient::ConnectViaWindowTreeFactory(
     service_manager::Connector* connector) {
   // The client id doesn't really matter, we use 101 purely for debugging.
   client_id_ = 101;
 
-  mojom::WindowTreeFactoryPtr factory;
+  ui::mojom::WindowTreeFactoryPtr factory;
   connector->ConnectToInterface("service:ui", &factory);
-  mojom::WindowTreePtr window_tree;
+  ui::mojom::WindowTreePtr window_tree;
   factory->CreateWindowTree(GetProxy(&window_tree),
                             binding_.CreateInterfacePtrAndBind());
   SetWindowTree(std::move(window_tree));
 }
 
 void WindowTreeClient::ConnectAsWindowManager(
     service_manager::Connector* connector) {
   DCHECK(window_manager_delegate_);
 
-  mojom::WindowManagerWindowTreeFactoryPtr factory;
+  ui::mojom::WindowManagerWindowTreeFactoryPtr factory;
   connector->ConnectToInterface("service:ui", &factory);
-  mojom::WindowTreePtr window_tree;
+  ui::mojom::WindowTreePtr window_tree;
   factory->CreateWindowTree(GetProxy(&window_tree),
                             binding_.CreateInterfacePtrAndBind());
   SetWindowTree(std::move(window_tree));
 }
 
 void WindowTreeClient::WaitForEmbed() {
   DCHECK(roots_.empty());
   // OnEmbed() is the first function called.
   binding_.WaitForIncomingMethodCall();
   // TODO(sky): deal with pipe being closed before we get OnEmbed().
 }
 
-void WindowTreeClient::DestroyWindow(Window* window) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<CrashInFlightChange>(window, ChangeType::DELETE_WINDOW));
-  tree_->DeleteWindow(change_id, server_id(window));
-}
-
-void WindowTreeClient::AddChild(Window* parent, Id child_id) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<CrashInFlightChange>(parent, ChangeType::ADD_CHILD));
-  tree_->AddWindow(change_id, parent->server_id(), child_id);
-}
-
-void WindowTreeClient::RemoveChild(Window* parent, Id child_id) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<CrashInFlightChange>(parent, ChangeType::REMOVE_CHILD));
-  tree_->RemoveWindowFromParent(change_id, child_id);
-}
-
-void WindowTreeClient::AddTransientWindow(Window* window,
-                                              Id transient_window_id) {
-  DCHECK(tree_);
-  const uint32_t change_id =
-      ScheduleInFlightChange(base::MakeUnique<CrashInFlightChange>(
-          window, ChangeType::ADD_TRANSIENT_WINDOW));
-  tree_->AddTransientWindow(change_id, server_id(window), transient_window_id);
-}
-
-void WindowTreeClient::RemoveTransientWindowFromParent(Window* window) {
-  DCHECK(tree_);
-  const uint32_t change_id =
-      ScheduleInFlightChange(base::MakeUnique<CrashInFlightChange>(
-          window, ChangeType::REMOVE_TRANSIENT_WINDOW_FROM_PARENT));
-  tree_->RemoveTransientWindowFromParent(change_id, server_id(window));
-}
-
-void WindowTreeClient::SetModal(Window* window) {
-  DCHECK(tree_);
-  const uint32_t change_id =
-      ScheduleInFlightChange(base::MakeUnique<InFlightSetModalChange>(window));
-  tree_->SetModal(change_id, server_id(window));
-}
-
-void WindowTreeClient::Reorder(Window* window,
-                                   Id relative_window_id,
-                                   mojom::OrderDirection direction) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<CrashInFlightChange>(window, ChangeType::REORDER));
-  tree_->ReorderWindow(change_id, server_id(window), relative_window_id,
-                       direction);
-}
-
-bool WindowTreeClient::WasCreatedByThisClient(const Window* window) const {
-  // Windows created via CreateTopLevelWindow() are not owned by us, but have
-  // our client id. const_cast is required by set.
-  return HiWord(server_id(window)) == client_id_ &&
-         roots_.count(const_cast<Window*>(window)) == 0;
-}
-
-void WindowTreeClient::SetBounds(Window* window,
-                                 const gfx::Rect& old_bounds,
-                                 const gfx::Rect& bounds) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightBoundsChange>(window, old_bounds));
-  tree_->SetWindowBounds(change_id, server_id(window), bounds);
-}
-
-void WindowTreeClient::SetCapture(Window* window) {
-  // In order for us to get here we had to have exposed a window, which implies
-  // we got a client.
-  DCHECK(tree_);
-  if (capture_window_ == window)
-    return;
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightCaptureChange>(this, capture_window_));
-  tree_->SetCapture(change_id, server_id(window));
-  LocalSetCapture(window);
-}
-
-void WindowTreeClient::ReleaseCapture(Window* window) {
-  // In order for us to get here we had to have exposed a window, which implies
-  // we got a client.
-  DCHECK(tree_);
-  if (capture_window_ != window)
-    return;
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightCaptureChange>(this, window));
-  tree_->ReleaseCapture(change_id, server_id(window));
-  LocalSetCapture(nullptr);
-}
-
 void WindowTreeClient::SetClientArea(
-    Id window_id,
+    Window* window,
     const gfx::Insets& client_area,
     const std::vector<gfx::Rect>& additional_client_areas) {
   DCHECK(tree_);
-  tree_->SetClientArea(window_id, client_area, additional_client_areas);
+  tree_->SetClientArea(WindowMus::Get(window)->server_id(), client_area,
+                       additional_client_areas);
 }
 
-void WindowTreeClient::SetHitTestMask(Id window_id, const gfx::Rect& mask) {
+void WindowTreeClient::SetHitTestMask(Window* window, const gfx::Rect& mask) {
   DCHECK(tree_);
-  tree_->SetHitTestMask(window_id, mask);
+  tree_->SetHitTestMask(WindowMus::Get(window)->server_id(), mask);
 }
 
-void WindowTreeClient::ClearHitTestMask(Id window_id) {
+void WindowTreeClient::ClearHitTestMask(Window* window) {
   DCHECK(tree_);
-  tree_->SetHitTestMask(window_id, base::nullopt);
+  tree_->SetHitTestMask(WindowMus::Get(window)->server_id(), base::nullopt);
 }
 
-void WindowTreeClient::SetFocus(Window* window) {
-  // In order for us to get here we had to have exposed a window, which implies
-  // we got a client.
+void WindowTreeClient::SetCanFocus(Window* window, bool can_focus) {
   DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightFocusChange>(this, focused_window_));
-  tree_->SetFocus(change_id, window ? server_id(window) : 0);
-  LocalSetFocus(window);
+  DCHECK(window);
+  tree_->SetCanFocus(WindowMus::Get(window)->server_id(), can_focus);
 }
 
-void WindowTreeClient::SetCanFocus(Id window_id, bool can_focus) {
+void WindowTreeClient::SetPredefinedCursor(WindowMus* window,
+                                           ui::mojom::Cursor old_cursor,
+                                           ui::mojom::Cursor new_cursor) {
   DCHECK(tree_);
-  tree_->SetCanFocus(window_id, can_focus);
+
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<InFlightPredefinedCursorChange>(window, old_cursor));
+  tree_->SetPredefinedCursor(change_id, window->server_id(), new_cursor);
 }
 
-void WindowTreeClient::SetPredefinedCursor(Id window_id,
-                                           ui::mojom::Cursor cursor_id) {
+void WindowTreeClient::SetWindowTextInputState(WindowMus* window,
+                                               mojo::TextInputStatePtr state) {
   DCHECK(tree_);
-
-  Window* window = GetWindowByServerId(window_id);
-  if (!window)
-    return;
-
-  // We make an inflight change thing here.
-  const uint32_t change_id =
-      ScheduleInFlightChange(base::MakeUnique<InFlightPredefinedCursorChange>(
-          window, window->predefined_cursor()));
-  tree_->SetPredefinedCursor(change_id, window_id, cursor_id);
+  tree_->SetWindowTextInputState(window->server_id(), std::move(state));
 }
 
-void WindowTreeClient::SetVisible(Window* window, bool visible) {
+void WindowTreeClient::SetImeVisibility(WindowMus* window,
+                                        bool visible,
+                                        mojo::TextInputStatePtr state) {
   DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightVisibleChange>(window, !visible));
-  tree_->SetWindowVisibility(change_id, server_id(window), visible);
+  tree_->SetImeVisibility(window->server_id(), visible, std::move(state));
 }
 
-void WindowTreeClient::SetOpacity(Window* window, float opacity) {
-  DCHECK(tree_);
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightOpacityChange>(window, window->opacity()));
-  tree_->SetWindowOpacity(change_id, server_id(window), opacity);
-}
-
-void WindowTreeClient::SetProperty(Window* window,
-                                       const std::string& name,
-                                       mojo::Array<uint8_t> data) {
-  DCHECK(tree_);
-
-  mojo::Array<uint8_t> old_value(nullptr);
-  if (window->HasSharedProperty(name))
-    old_value = mojo::Array<uint8_t>::From(window->properties_[name]);
-
-  const uint32_t change_id = ScheduleInFlightChange(
-      base::MakeUnique<InFlightPropertyChange>(window, name, old_value));
-  tree_->SetWindowProperty(change_id, server_id(window), mojo::String(name),
-                           std::move(data));
-}
-
-void WindowTreeClient::SetWindowTextInputState(
+void WindowTreeClient::Embed(
     Id window_id,
-    mojo::TextInputStatePtr state) {
-  DCHECK(tree_);
-  tree_->SetWindowTextInputState(window_id, std::move(state));
-}
-
-void WindowTreeClient::SetImeVisibility(Id window_id,
-                                            bool visible,
-                                            mojo::TextInputStatePtr state) {
-  DCHECK(tree_);
-  tree_->SetImeVisibility(window_id, visible, std::move(state));
-}
-
-void WindowTreeClient::Embed(Id window_id,
-                             mojom::WindowTreeClientPtr client,
-                             uint32_t flags,
-                             const mojom::WindowTree::EmbedCallback& callback) {
+    ui::mojom::WindowTreeClientPtr client,
+    uint32_t flags,
+    const ui::mojom::WindowTree::EmbedCallback& callback) {
   DCHECK(tree_);
   tree_->Embed(window_id, std::move(client), flags, callback);
 }
 
 void WindowTreeClient::RequestClose(Window* window) {
+  DCHECK(window);
   if (window_manager_internal_client_)
-    window_manager_internal_client_->WmRequestClose(server_id(window));
+    window_manager_internal_client_->WmRequestClose(
+        WindowMus::Get(window)->server_id());
 }
 
 void WindowTreeClient::AttachCompositorFrameSink(
     Id window_id,
-    mojom::CompositorFrameSinkType type,
+    ui::mojom::CompositorFrameSinkType type,
     cc::mojom::MojoCompositorFrameSinkRequest compositor_frame_sink,
     cc::mojom::MojoCompositorFrameSinkClientPtr client) {
   DCHECK(tree_);
   tree_->AttachCompositorFrameSink(
       window_id, type, std::move(compositor_frame_sink), std::move(client));
 }
 
-void WindowTreeClient::OnWindowSurfaceDetached(
-    Id window_id,
-    const cc::SurfaceSequence& sequence) {
-  DCHECK(tree_);
-  tree_->OnWindowSurfaceDetached(window_id, sequence);
+void WindowTreeClient::RegisterWindowMus(WindowMus* window) {
+  DCHECK(windows_.find(window->server_id()) == windows_.end());
+  windows_[window->server_id()] = window;
 }
 
-void WindowTreeClient::LocalSetCapture(Window* window) {
+WindowMus* WindowTreeClient::GetWindowByServerId(Id id) {
+  IdToWindowMap::const_iterator it = windows_.find(id);
+  return it != windows_.end() ? it->second : nullptr;
+}
+
+bool WindowTreeClient::WasCreatedByThisClient(const WindowMus* window) const {
+  // Windows created via CreateTopLevelWindow() are not owned by us, but have
+  // our client id. const_cast is required by set.
+  return HiWord(window->server_id()) == client_id_ &&
+         roots_.count(const_cast<WindowMus*>(window)) == 0;
+}
+
+void WindowTreeClient::SetFocusFromServer(WindowMus* window) {
+  if (focused_window_ == window)
+    return;
+
+  if (window) {
+    client::FocusClient* focus_client =
+        client::GetFocusClient(window->GetWindow());
+    if (focus_client) {
+      SetFocusFromServerImpl(focus_client, window);
+    } else {
+      SetFocusFromServerImpl(
+          client::GetFocusClient(focused_window_->GetWindow()), nullptr);
+    }
+  } else {
+    SetFocusFromServerImpl(client::GetFocusClient(focused_window_->GetWindow()),
+                           nullptr);
+  }
+}
+
+void WindowTreeClient::SetFocusFromServerImpl(client::FocusClient* focus_client,
+                                              WindowMus* window) {
+  if (!focus_client)
+    return;
+
+  DCHECK(!setting_focus_);
+  base::AutoReset<bool> focus_reset(&setting_focus_, true);
+  base::AutoReset<WindowMus*> window_setting_focus_to_reset(
+      &window_setting_focus_to_, window);
+  focus_client->FocusWindow(window ? window->GetWindow() : nullptr);
+}
+
+void WindowTreeClient::SetCaptureFromServer(WindowMus* window) {
+  // In order for us to get here we had to have exposed a window, which implies
+  // we got a client.
+  DCHECK(tree_);
   if (capture_window_ == window)
     return;
-  Window* lost_capture = capture_window_;
-  capture_window_ = window;
-  if (lost_capture) {
-    for (auto& observer : *WindowPrivate(lost_capture).observers())
-      observer.OnWindowLostCapture(lost_capture);
-  }
-  for (auto& observer : observers_)
-    observer.OnWindowTreeCaptureChanged(window, lost_capture);
-}
-
-void WindowTreeClient::LocalSetFocus(Window* focused) {
-  Window* blurred = focused_window_;
-  // Update |focused_window_| before calling any of the observers, so that the
-  // observers get the correct result from calling |Window::HasFocus()|,
-  // |WindowTreeClient::GetFocusedWindow()| etc.
-  focused_window_ = focused;
-  if (blurred) {
-    for (auto& observer : *WindowPrivate(blurred).observers())
-      observer.OnWindowFocusChanged(focused, blurred);
-  }
-  if (focused) {
-    for (auto& observer : *WindowPrivate(focused).observers())
-      observer.OnWindowFocusChanged(focused, blurred);
-  }
-  for (auto& observer : observers_)
-    observer.OnWindowTreeFocusChanged(focused, blurred);
-}
-
-void WindowTreeClient::AddWindow(Window* window) {
-  DCHECK(windows_.find(server_id(window)) == windows_.end());
-  windows_[server_id(window)] = window;
-}
-
-void WindowTreeClient::OnWindowDestroying(Window* window) {
-  if (window == capture_window_) {
-    // Normally the queue updates itself upon window destruction. However since
-    // |window| is being destroyed, it will not be possible to notify its
-    // observers of the lost capture. Update local state now.
-    LocalSetCapture(nullptr);
-  }
-  // For |focused_window_| window destruction clears the entire focus state.
-}
-
-void WindowTreeClient::OnWindowDestroyed(Window* window) {
-  windows_.erase(server_id(window));
-
-  for (auto& entry : embedded_windows_) {
-    auto it = entry.second.find(window);
-    if (it != entry.second.end()) {
-      entry.second.erase(it);
-      break;
-    }
-  }
-
-  // Remove any InFlightChanges associated with the window.
-  std::set<uint32_t> in_flight_change_ids_to_remove;
-  for (const auto& pair : in_flight_map_) {
-    if (pair.second->window() == window)
-      in_flight_change_ids_to_remove.insert(pair.first);
-  }
-  for (auto change_id : in_flight_change_ids_to_remove)
-    in_flight_map_.erase(change_id);
-
-  const bool was_root = roots_.erase(window) > 0;
-  if (!in_destructor_ && was_root && roots_.empty() && is_from_embed_)
-    delegate_->OnEmbedRootDestroyed(window);
-}
-
-Window* WindowTreeClient::GetWindowByServerId(Id id) {
-  IdToWindowMap::const_iterator it = windows_.find(id);
-  return it != windows_.end() ? it->second : NULL;
+  DCHECK(!setting_capture_);
+  base::AutoReset<bool> capture_reset(&setting_capture_, true);
+  base::AutoReset<WindowMus*> window_setting_capture_to_reset(
+      &window_setting_capture_to_, window);
+  delegate_->GetCaptureClient()->SetCapture(window ? window->GetWindow()
+                                                   : nullptr);
 }
 
 InFlightChange* WindowTreeClient::GetOldestInFlightChangeMatching(
     const InFlightChange& change) {
   for (const auto& pair : in_flight_map_) {
     if (pair.second->window() == change.window() &&
         pair.second->change_type() == change.change_type() &&
         pair.second->Matches(change)) {
       return pair.second.get();
     }
@@ skipping 13 matching lines @@
 bool WindowTreeClient::ApplyServerChangeToExistingInFlightChange(
     const InFlightChange& change) {
   InFlightChange* existing_change = GetOldestInFlightChangeMatching(change);
   if (!existing_change)
     return false;
 
   existing_change->SetRevertValueFrom(change);
   return true;
 }
 
-Window* WindowTreeClient::BuildWindowTree(
-    const mojo::Array<mojom::WindowDataPtr>& windows,
-    Window* initial_parent) {
-  std::vector<Window*> parents;
-  Window* root = nullptr;
-  Window* last_window = nullptr;
+void WindowTreeClient::BuildWindowTree(
+    const mojo::Array<ui::mojom::WindowDataPtr>& windows,
+    WindowMus* initial_parent) {
+  std::vector<WindowMus*> parents;
+  WindowMus* last_window = nullptr;
   if (initial_parent)
     parents.push_back(initial_parent);
-  for (size_t i = 0; i < windows.size(); ++i) {
-    if (last_window && windows[i]->parent_id == server_id(last_window)) {
+  for (const auto& window_data : windows) {
+    if (last_window && window_data->parent_id == last_window->server_id()) {
       parents.push_back(last_window);
     } else if (!parents.empty()) {
-      while (server_id(parents.back()) != windows[i]->parent_id)
+      while (parents.back()->server_id() != window_data->parent_id)
         parents.pop_back();
     }
-    Window* window = AddWindowToClient(
-        this, !parents.empty() ? parents.back() : nullptr, windows[i]);
-    if (!last_window)
-      root = window;
-    last_window = window;
+    // This code is only called in a context where there is a parent.
+    DCHECK(!parents.empty());
+    last_window = NewWindowFromWindowData(
+        !parents.empty() ? parents.back() : nullptr, window_data);
   }
-  return root;
 }
 
-Window* WindowTreeClient::NewWindowImpl(
-    NewWindowType type,
-    const Window::SharedProperties* properties) {
-  DCHECK(tree_);
-  Window* window =
-      new Window(this, MakeTransportId(client_id_, next_window_id_++));
-  if (properties)
-    window->properties_ = *properties;
-  AddWindow(window);
-
-  const uint32_t change_id =
-      ScheduleInFlightChange(base::MakeUnique<CrashInFlightChange>(
-          window, type == NewWindowType::CHILD
-                      ? ChangeType::NEW_WINDOW
-                      : ChangeType::NEW_TOP_LEVEL_WINDOW));
-  mojo::Map<mojo::String, mojo::Array<uint8_t>> transport_properties;
-  if (properties) {
-    transport_properties =
-        mojo::Map<mojo::String, mojo::Array<uint8_t>>::From(*properties);
-  }
-  if (type == NewWindowType::CHILD) {
-    tree_->NewWindow(change_id, server_id(window),
-                     std::move(transport_properties));
-  } else {
-    roots_.insert(window);
-    tree_->NewTopLevelWindow(change_id, server_id(window),
-                             std::move(transport_properties));
-  }
-  return window;
+std::unique_ptr<WindowPortMus> WindowTreeClient::CreateWindowPortMus(
+    const ui::mojom::WindowDataPtr& window_data) {
+  std::unique_ptr<WindowPortMus> window_port_mus(
+      base::MakeUnique<WindowPortMus>(this));
+  window_port_mus->set_server_id(window_data->window_id);
+  RegisterWindowMus(window_port_mus.get());
+  return window_port_mus;
 }
 
-void WindowTreeClient::SetWindowTree(mojom::WindowTreePtr window_tree_ptr) {
+void WindowTreeClient::SetLocalPropertiesFromServerProperties(
+    WindowMus* window,
+    const ui::mojom::WindowDataPtr& window_data) {
+  for (auto& pair : window_data->properties) {
+    if (pair.second.is_null()) {
+      window->SetPropertyFromServer(pair.first, nullptr);
+    } else {
+      std::vector<uint8_t> stl_value = pair.second.To<std::vector<uint8_t>>();
+      window->SetPropertyFromServer(pair.first, &stl_value);
+    }
+  }
+}
+
+Window* WindowTreeClient::CreateWindowTreeHost(
+    WindowTreeHostType type,
+    const ui::mojom::WindowDataPtr& window_data,
+    Window* content_window) {
+  Window* user_window = nullptr;
+  switch (type) {
+    case WindowTreeHostType::DISPLAY: {
+      DCHECK(!content_window);
+      WindowTreeHost* window_tree_host =
+          new WindowTreeHostMus(CreateWindowPortMus(window_data));
+      user_window = window_tree_host->window();
+      break;
+    }
+    case WindowTreeHostType::EMBED: {
+      DCHECK(!content_window);
+      user_window = new Window(nullptr, CreateWindowPortMus(window_data));
+      user_window->Init(ui::LAYER_TEXTURED);
+      new WindowTreeHostMus(nullptr, user_window);
+      break;
+    }
+    case WindowTreeHostType::TOP_LEVEL: {
+      DCHECK(content_window);
+      user_window = content_window;
+      new WindowTreeHostMus(nullptr, user_window);
+      break;
+    }
+  }
+  WindowMus* user_window_mus = WindowMus::Get(user_window);
+  roots_.insert(user_window_mus);
+  if (!window_data.is_null())
+    SetLocalPropertiesFromServerProperties(user_window_mus, window_data);
+  return user_window;
+}
+
+WindowMus* WindowTreeClient::NewWindowFromWindowData(
+    WindowMus* parent,
+    const ui::mojom::WindowDataPtr& window_data) {
+  std::unique_ptr<WindowPortMus> window_port_mus(
+      CreateWindowPortMus(window_data));
+  WindowPortMus* window_port_mus_ptr = window_port_mus.get();
+  Window* window = new Window(nullptr, std::move(window_port_mus));
+  WindowMus* window_mus = window_port_mus_ptr;
+  window->Init(ui::LAYER_NOT_DRAWN);
+  SetLocalPropertiesFromServerProperties(window_mus, window_data);
+  window_mus->SetBoundsFromServer(window_data->bounds);
+  if (parent)
+    parent->AddChildFromServer(window_port_mus_ptr);
+  if (window_data->visible)
+    window_mus->SetVisibleFromServer(true);
+  return window_port_mus_ptr;
+}
+
+void WindowTreeClient::SetWindowTree(ui::mojom::WindowTreePtr window_tree_ptr) {
   tree_ptr_ = std::move(window_tree_ptr);
   tree_ = tree_ptr_.get();
 
   tree_ptr_->GetCursorLocationMemory(
       base::Bind(&WindowTreeClient::OnReceivedCursorLocationMemory,
                  weak_factory_.GetWeakPtr()));
 
   tree_ptr_.set_connection_error_handler(base::Bind(
       &WindowTreeClient::OnConnectionLost, weak_factory_.GetWeakPtr()));
 
   if (window_manager_delegate_) {
     tree_ptr_->GetWindowManagerClient(GetProxy(&window_manager_internal_client_,
                                                tree_ptr_.associated_group()));
   }
 }
 
 void WindowTreeClient::OnConnectionLost() {
   delegate_->OnLostConnection(this);
 }
 
-void WindowTreeClient::OnEmbedImpl(mojom::WindowTree* window_tree,
-                                       ClientSpecificId client_id,
-                                       mojom::WindowDataPtr root_data,
-                                       int64_t display_id,
-                                       Id focused_window_id,
-                                       bool drawn) {
+void WindowTreeClient::OnEmbedImpl(ui::mojom::WindowTree* window_tree,
+                                   ClientSpecificId client_id,
+                                   ui::mojom::WindowDataPtr root_data,
+                                   int64_t display_id,
+                                   Id focused_window_id,
+                                   bool drawn) {
   // WARNING: this is only called if WindowTreeClient was created as the
   // result of an embedding.
   tree_ = window_tree;
   client_id_ = client_id;
 
   DCHECK(roots_.empty());
-  Window* root = AddWindowToClient(this, nullptr, root_data);
-  WindowPrivate(root).LocalSetDisplay(display_id);
-  roots_.insert(root);
+  Window* root =
+      CreateWindowTreeHost(WindowTreeHostType::EMBED, root_data, nullptr);
+  // TODO: needs to deal with drawn and display_id.
 
-  focused_window_ = GetWindowByServerId(focused_window_id);
-
-  WindowPrivate(root).LocalSetParentDrawn(drawn);
+  SetFocusFromServer(GetWindowByServerId(focused_window_id));
 
   delegate_->OnEmbed(root);
-
-  if (focused_window_) {
-    for (auto& observer : observers_)
-      observer.OnWindowTreeFocusChanged(focused_window_, nullptr);
-  }
 }
 
-void WindowTreeClient::WmNewDisplayAddedImpl(const display::Display& display,
-                                             mojom::WindowDataPtr root_data,
-                                             bool parent_drawn) {
+WindowTreeHost* WindowTreeClient::WmNewDisplayAddedImpl(
+    const display::Display& display,
+    ui::mojom::WindowDataPtr root_data,
+    bool parent_drawn) {
   DCHECK(window_manager_delegate_);
 
-  Window* root = AddWindowToClient(this, nullptr, root_data);
-  WindowPrivate(root).LocalSetDisplay(display.id());
-  WindowPrivate(root).LocalSetParentDrawn(parent_drawn);
-  roots_.insert(root);
+  // TODO: need to deal with display_id and drawn.
+  Window* root =
+      CreateWindowTreeHost(WindowTreeHostType::DISPLAY, root_data, nullptr);
+  // WindowPrivate(root).LocalSetDisplay(display.id());
+  // WindowPrivate(root).LocalSetParentDrawn(parent_drawn);
 
   window_manager_delegate_->OnWmNewDisplay(root, display);
+  return root->GetHost();
+}
+
+std::unique_ptr<EventResultCallback>
+WindowTreeClient::CreateEventResultCallback(int32_t event_id) {
+  return base::MakeUnique<EventResultCallback>(
+      base::Bind(&ui::mojom::WindowTree::OnWindowInputEventAck,
+                 base::Unretained(tree_), event_id));
 }
 
 void WindowTreeClient::OnReceivedCursorLocationMemory(
     mojo::ScopedSharedBufferHandle handle) {
   cursor_location_mapping_ = handle->Map(sizeof(base::subtle::Atomic32));
   DCHECK(cursor_location_mapping_);
 }
 
+std::unique_ptr<WindowPortInitData> WindowTreeClient::OnWindowMusCreated(
+    WindowMus* window) {
+  if (window->server_id() != 0) {
+    // This window was created by us and has an associated server window.
+    return nullptr;
+  }
+
+  window->set_server_id(MakeTransportId(client_id_, next_window_id_++));
+  RegisterWindowMus(window);
+
+  const bool create_top_level =
+      !window_manager_delegate_ &&
+      ShouldCreateTopLevel(window->GetWindow()->type());
+
+  mojo::Map<mojo::String, mojo::Array<uint8_t>> transport_properties;
+  std::set<const void*> property_keys =
+      window->GetWindow()->GetAllPropertKeys();
+  PropertyConverter* property_converter = delegate_->GetPropertyConverter();
+  for (const void* key : property_keys) {
+    std::string transport_name;
+    std::unique_ptr<std::vector<uint8_t>> transport_value;
+    if (!property_converter->ConvertPropertyForTransport(
+            window->GetWindow(), key, &transport_name, &transport_value)) {
+      continue;
+    }
+    if (!transport_value) {
+      transport_properties[transport_name] = mojo::Array<uint8_t>(nullptr);
+    } else {
+      transport_properties[transport_name] =
+          mojo::Array<uint8_t>::From(*transport_value);
+    }
+  }
+
+  const uint32_t change_id =
+      ScheduleInFlightChange(base::MakeUnique<CrashInFlightChange>(
+          window, create_top_level ? ChangeType::NEW_TOP_LEVEL_WINDOW
+                                   : ChangeType::NEW_WINDOW));
+  if (create_top_level) {
+    std::unique_ptr<WindowPortInitData> data(
+        base::MakeUnique<WindowPortInitData>());
+    tree_->NewTopLevelWindow(change_id, window->server_id(),
+                             std::move(transport_properties));
+    return data;
+  }
+  tree_->NewWindow(change_id, window->server_id(),
+                   std::move(transport_properties));
+  return nullptr;
+}
+
+void WindowTreeClient::OnWindowMusInitDone(
+    WindowMus* window,
+    std::unique_ptr<WindowPortInitData> init_data) {
+  if (!init_data)
+    return;
+
+  // Delay creating the WindowTreeHost until after Init(), otherwise we trigger
+  // crashes in code that expects window parenting to happen after
+  // Env::NotifyWindowInitialized() is called.
+  CreateWindowTreeHost(WindowTreeHostType::TOP_LEVEL, nullptr,
+                       window->GetWindow());
+}
+
+void WindowTreeClient::OnWindowMusDestroyed(WindowMus* window) {
+  if (focused_window_ == window)
+    focused_window_ = nullptr;
+
+  // TODO: decide how to deal with windows not owned by this client.
+  if (WasCreatedByThisClient(window) || IsRoot(window)) {
+    const uint32_t change_id =
+        ScheduleInFlightChange(base::MakeUnique<CrashInFlightChange>(
+            window, ChangeType::DELETE_WINDOW));
+    tree_->DeleteWindow(change_id, window->server_id());
+  }
+
+  windows_.erase(window->server_id());
+
+  for (auto& entry : embedded_windows_) {
+    auto it = entry.second.find(window->GetWindow());
+    if (it != entry.second.end()) {
+      entry.second.erase(it);
+      break;
+    }
+  }
+
+  // Remove any InFlightChanges associated with the window.
+  std::set<uint32_t> in_flight_change_ids_to_remove;
+  for (const auto& pair : in_flight_map_) {
+    if (pair.second->window() == window)
+      in_flight_change_ids_to_remove.insert(pair.first);
+  }
+  for (auto change_id : in_flight_change_ids_to_remove)
+    in_flight_map_.erase(change_id);
+
+  const bool was_root = roots_.erase(window) > 0;
+  if (!in_destructor_ && was_root && roots_.empty() && is_from_embed_)
+    delegate_->OnEmbedRootDestroyed(window->GetWindow());
+}
+
+void WindowTreeClient::OnWindowMusBoundsChanged(WindowMus* window,
+                                                const gfx::Rect& old_bounds,
+                                                const gfx::Rect& new_bounds) {
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<InFlightBoundsChange>(window, old_bounds));
+  tree_->SetWindowBounds(change_id, window->server_id(), new_bounds);
+}
+
+void WindowTreeClient::OnWindowMusAddChild(WindowMus* parent,
+                                           WindowMus* child) {
+  // TODO: add checks to ensure this can work.
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<CrashInFlightChange>(parent, ChangeType::ADD_CHILD));
+  tree_->AddWindow(change_id, parent->server_id(), child->server_id());
+}
+
+void WindowTreeClient::OnWindowMusRemoveChild(WindowMus* parent,
+                                              WindowMus* child) {
+  // TODO: add checks to ensure this can work.
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<CrashInFlightChange>(parent, ChangeType::REMOVE_CHILD));
+  tree_->RemoveWindowFromParent(change_id, child->server_id());
+}
+
+void WindowTreeClient::OnWindowMusMoveChild(WindowMus* parent,
+                                            size_t current_index,
+                                            size_t dest_index) {
+  // TODO: add checks to ensure this can work, e.g. we own the parent.
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<CrashInFlightChange>(parent, ChangeType::REORDER));
+  WindowMus* window =
+      WindowMus::Get(parent->GetWindow()->children()[current_index]);
+  WindowMus* relative_window = nullptr;
+  ui::mojom::OrderDirection direction;
+  if (dest_index < current_index) {
+    relative_window =
+        WindowMus::Get(parent->GetWindow()->children()[dest_index]);
+    direction = ui::mojom::OrderDirection::BELOW;
+  } else {
+    relative_window =
+        WindowMus::Get(parent->GetWindow()->children()[dest_index]);
+    direction = ui::mojom::OrderDirection::ABOVE;
+  }
+  tree_->ReorderWindow(change_id, window->server_id(),
+                       relative_window->server_id(), direction);
+}
+
+void WindowTreeClient::OnWindowMusSetVisible(WindowMus* window, bool visible) {
+  // TODO: add checks to ensure this can work.
+  DCHECK(tree_);
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<InFlightVisibleChange>(window, !visible));
+  tree_->SetWindowVisibility(change_id, window->server_id(), visible);
+}
+
+std::unique_ptr<WindowPortPropertyData>
+WindowTreeClient::OnWindowMusWillChangeProperty(WindowMus* window,
+                                                const void* key) {
+  std::unique_ptr<WindowPortPropertyDataMus> data(
+      base::MakeUnique<WindowPortPropertyDataMus>());
+  if (!delegate_->GetPropertyConverter()->ConvertPropertyForTransport(
+          window->GetWindow(), key, &data->transport_name,
+          &data->transport_value)) {
+    return nullptr;
+  }
+  return std::move(data);
+}
+
+void WindowTreeClient::OnWindowMusPropertyChanged(
+    WindowMus* window,
+    const void* key,
+    std::unique_ptr<WindowPortPropertyData> data) {
+  if (!data)
+    return;
+  WindowPortPropertyDataMus* data_mus =
+      static_cast<WindowPortPropertyDataMus*>(data.get());
+
+  std::string transport_name;
+  std::unique_ptr<std::vector<uint8_t>> transport_value;
+  if (!delegate_->GetPropertyConverter()->ConvertPropertyForTransport(
+          window->GetWindow(), key, &transport_name, &transport_value)) {
+    return;
+  }
+  DCHECK_EQ(transport_name, data_mus->transport_name);
+
+  mojo::Array<uint8_t> transport_value_mojo(nullptr);
+  if (transport_value) {
+    transport_value_mojo.resize(transport_value->size());
+    if (transport_value->size()) {
+      memcpy(&transport_value_mojo.front(), &(transport_value->front()),
+             transport_value->size());
+    }
+  }
+  const uint32_t change_id =
+      ScheduleInFlightChange(base::MakeUnique<InFlightPropertyChange>(
+          window, transport_name, std::move(data_mus->transport_value)));
+  tree_->SetWindowProperty(change_id, window->server_id(),
+                           mojo::String(transport_name),
+                           std::move(transport_value_mojo));
+}
+
+void WindowTreeClient::OnWindowMusSurfaceDetached(
+    WindowMus* window,
+    const cc::SurfaceSequence& sequence) {
+  tree_->OnWindowSurfaceDetached(window->server_id(), sequence);
+}
+
 void WindowTreeClient::OnWmMoveLoopCompleted(uint32_t change_id,
                                              bool completed) {
   if (window_manager_internal_client_)
     window_manager_internal_client_->WmResponse(change_id, completed);
 
   if (change_id == current_wm_move_loop_change_) {
     current_wm_move_loop_change_ = 0;
     current_wm_move_loop_window_id_ = 0;
   }
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeClient, WindowTreeClient implementation:
 
-const std::set<Window*>& WindowTreeClient::GetRoots() {
-  return roots_;
+std::set<Window*> WindowTreeClient::GetRoots() {
+  std::set<Window*> roots;
+  for (WindowMus* window : roots_)
+    roots.insert(window->GetWindow());
+  return roots;
 }
 
 Window* WindowTreeClient::GetFocusedWindow() {
-  return focused_window_;
-}
-
-void WindowTreeClient::ClearFocus() {
-  if (!focused_window_)
-    return;
-
-  SetFocus(nullptr);
+  return focused_window_ ? focused_window_->GetWindow() : nullptr;
 }
 
 gfx::Point WindowTreeClient::GetCursorScreenPoint() {
   // We raced initialization. Return (0, 0).
   if (!cursor_location_memory())
     return gfx::Point();
 
   base::subtle::Atomic32 location =
       base::subtle::NoBarrier_Load(cursor_location_memory());
   return gfx::Point(static_cast<int16_t>(location >> 16),
@@ skipping 13 matching lines @@
   has_pointer_watcher_ = false;
 }
 
 void WindowTreeClient::PerformDragDrop(
     Window* window,
     const std::map<std::string, std::vector<uint8_t>>& drag_data,
     int drag_operation,
     const gfx::Point& cursor_location,
     const SkBitmap& bitmap,
     const base::Callback<void(bool, uint32_t)>& callback) {
+  // TODO: dnd.
+  /*
   DCHECK(!current_drag_state_);
 
   // TODO(erg): Pass |cursor_location| and |bitmap| in PerformDragDrop() when
   // we start showing an image representation of the drag under he cursor.
 
   if (window->drop_target()) {
     // To minimize the number of round trips, copy the drag drop data to our
     // handler here, instead of forcing mus to send this same data back.
     OnDragDropStart(
         mojo::Map<mojo::String, mojo::Array<uint8_t>>::From(drag_data));
   }
 
   uint32_t current_drag_change = ScheduleInFlightChange(
       base::MakeUnique<InFlightDragChange>(window, ChangeType::DRAG_LOOP));
   current_drag_state_.reset(new CurrentDragState{
       current_drag_change, ui::mojom::kDropEffectNone, callback});
 
   tree_->PerformDragDrop(
       current_drag_change, window->server_id(),
       mojo::Map<mojo::String, mojo::Array<uint8_t>>::From(drag_data),
       drag_operation);
+  */
 }
 
 void WindowTreeClient::CancelDragDrop(Window* window) {
   // Server will clean up drag and fail the in-flight change.
-  tree_->CancelDragDrop(window->server_id());
+  tree_->CancelDragDrop(WindowMus::Get(window)->server_id());
 }
 
 void WindowTreeClient::PerformWindowMove(
     Window* window,
     ui::mojom::MoveLoopSource source,
     const gfx::Point& cursor_location,
     const base::Callback<void(bool)>& callback) {
   DCHECK(on_current_move_finished_.is_null());
   on_current_move_finished_ = callback;
 
+  WindowMus* window_mus = WindowMus::Get(window);
   current_move_loop_change_ = ScheduleInFlightChange(
-      base::MakeUnique<InFlightDragChange>(window, ChangeType::MOVE_LOOP));
+      base::MakeUnique<InFlightDragChange>(window_mus, ChangeType::MOVE_LOOP));
   // Tell the window manager to take over moving us.
-  tree_->PerformWindowMove(current_move_loop_change_, window->server_id(),
+  tree_->PerformWindowMove(current_move_loop_change_, window_mus->server_id(),
                            source, cursor_location);
 }
 
 void WindowTreeClient::CancelWindowMove(Window* window) {
-  tree_->CancelWindowMove(window->server_id());
+  tree_->CancelWindowMove(WindowMus::Get(window)->server_id());
 }
 
-Window* WindowTreeClient::NewWindow(
-    const Window::SharedProperties* properties) {
-  return NewWindowImpl(NewWindowType::CHILD, properties);
-}
-
-Window* WindowTreeClient::NewTopLevelWindow(
-    const Window::SharedProperties* properties) {
-  Window* window = NewWindowImpl(NewWindowType::TOP_LEVEL, properties);
-  // Assume newly created top level windows are drawn by default, otherwise
-  // requests to focus will fail. We will get the real value in
-  // OnTopLevelCreated().
-  window->LocalSetParentDrawn(true);
-  return window;
-}
-
-#if !defined(NDEBUG)
-std::string WindowTreeClient::GetDebugWindowHierarchy() const {
-  std::string result;
-  for (Window* root : roots_)
-    BuildDebugInfo(std::string(), root, &result);
-  return result;
-}
-
-void WindowTreeClient::BuildDebugInfo(const std::string& depth,
-                                      Window* window,
-                                      std::string* result) const {
-  std::string name = window->GetName();
-  *result += base::StringPrintf(
-      "%sid=%d visible=%s bounds=%d,%d %dx%d %s\n", depth.c_str(),
-      window->server_id(), window->visible() ? "true" : "false",
-      window->bounds().x(), window->bounds().y(), window->bounds().width(),
-      window->bounds().height(), !name.empty() ? name.c_str() : "(no name)");
-  for (Window* child : window->children())
-    BuildDebugInfo(depth + "  ", child, result);
-}
-#endif  // !defined(NDEBUG)
-
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeClient, WindowTreeClient implementation:
 
 void WindowTreeClient::AddObserver(WindowTreeClientObserver* observer) {
   observers_.AddObserver(observer);
 }
 
 void WindowTreeClient::RemoveObserver(WindowTreeClientObserver* observer) {
   observers_.RemoveObserver(observer);
 }
 
 void WindowTreeClient::SetCanAcceptDrops(Id window_id, bool can_accept_drops) {
   DCHECK(tree_);
   tree_->SetCanAcceptDrops(window_id, can_accept_drops);
 }
 
 void WindowTreeClient::SetCanAcceptEvents(Id window_id,
                                           bool can_accept_events) {
   DCHECK(tree_);
   tree_->SetCanAcceptEvents(window_id, can_accept_events);
 }
 
 void WindowTreeClient::OnEmbed(ClientSpecificId client_id,
-                               mojom::WindowDataPtr root_data,
-                               mojom::WindowTreePtr tree,
+                               ui::mojom::WindowDataPtr root_data,
+                               ui::mojom::WindowTreePtr tree,
                                int64_t display_id,
                                Id focused_window_id,
                                bool drawn) {
   DCHECK(!tree_ptr_);
   tree_ptr_ = std::move(tree);
 
   is_from_embed_ = true;
 
   if (window_manager_delegate_) {
     tree_ptr_->GetWindowManagerClient(GetProxy(&window_manager_internal_client_,
                                                tree_ptr_.associated_group()));
   }
 
   OnEmbedImpl(tree_ptr_.get(), client_id, std::move(root_data), display_id,
               focused_window_id, drawn);
 }
 
 void WindowTreeClient::OnEmbeddedAppDisconnected(Id window_id) {
-  Window* window = GetWindowByServerId(window_id);
-  if (window) {
-    for (auto& observer : *WindowPrivate(window).observers())
-      observer.OnWindowEmbeddedAppDisconnected(window);
-  }
+  WindowMus* window = GetWindowByServerId(window_id);
+  if (window)
+    window->NotifyEmbeddedAppDisconnected();
 }
 
 void WindowTreeClient::OnUnembed(Id window_id) {
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
-  delegate_->OnUnembed(window);
-  WindowPrivate(window).LocalDestroy();
+  delegate_->OnUnembed(window->GetWindow());
+  delete window;
 }
 
 void WindowTreeClient::OnCaptureChanged(Id new_capture_window_id,
                                         Id old_capture_window_id) {
-  Window* new_capture_window = GetWindowByServerId(new_capture_window_id);
-  Window* lost_capture_window = GetWindowByServerId(old_capture_window_id);
+  WindowMus* new_capture_window = GetWindowByServerId(new_capture_window_id);
+  WindowMus* lost_capture_window = GetWindowByServerId(old_capture_window_id);
   if (!new_capture_window && !lost_capture_window)
     return;
 
   InFlightCaptureChange change(this, new_capture_window);
   if (ApplyServerChangeToExistingInFlightChange(change))
     return;
 
-  LocalSetCapture(new_capture_window);
+  SetCaptureFromServer(new_capture_window);
 }
 
 void WindowTreeClient::OnTopLevelCreated(uint32_t change_id,
-                                             mojom::WindowDataPtr data,
-                                             int64_t display_id,
-                                             bool drawn) {
+                                         ui::mojom::WindowDataPtr data,
+                                         int64_t display_id,
+                                         bool drawn) {
   // The server ack'd the top level window we created and supplied the state
   // of the window at the time the server created it. For properties we do not
   // have changes in flight for we can update them immediately. For properties
   // with changes in flight we set the revert value from the server.
 
   if (!in_flight_map_.count(change_id)) {
     // The window may have been destroyed locally before the server could finish
     // creating the window, and before the server received the notification that
     // the window has been destroyed.
     return;
   }
   std::unique_ptr<InFlightChange> change(std::move(in_flight_map_[change_id]));
   in_flight_map_.erase(change_id);
 
-  Window* window = change->window();
-  WindowPrivate window_private(window);
+  WindowMus* window = change->window();
 
+  // TODO: parent drawn and display_id need to route to WindowTreeHost.
   // Drawn state and display-id always come from the server (they can't be
   // modified locally).
-  window_private.LocalSetParentDrawn(drawn);
-  window_private.LocalSetDisplay(display_id);
 
   // The default visibilty is false, we only need update visibility if it
   // differs from that.
   if (data->visible) {
     InFlightVisibleChange visible_change(window, data->visible);
     InFlightChange* current_change =
         GetOldestInFlightChangeMatching(visible_change);
     if (current_change)
       current_change->SetRevertValueFrom(visible_change);
     else
-      window_private.LocalSetVisible(true);
+      window->SetVisibleFromServer(true);
   }
 
   const gfx::Rect bounds(data->bounds);
   {
     InFlightBoundsChange bounds_change(window, bounds);
     InFlightChange* current_change =
         GetOldestInFlightChangeMatching(bounds_change);
     if (current_change)
       current_change->SetRevertValueFrom(bounds_change);
-    else if (window->bounds() != bounds)
-      window_private.LocalSetBounds(window->bounds(), bounds);
+    else if (window->GetWindow()->bounds() != bounds)
+      window->SetBoundsFromServer(bounds);
   }
 
   // There is currently no API to bulk set properties, so we iterate over each
   // property individually.
-  Window::SharedProperties properties =
+  std::map<std::string, std::vector<uint8_t>> properties =
       data->properties.To<std::map<std::string, std::vector<uint8_t>>>();
   for (const auto& pair : properties) {
-    InFlightPropertyChange property_change(
-        window, pair.first, mojo::Array<uint8_t>::From(pair.second));
+    std::unique_ptr<std::vector<uint8_t>> revert_value(
+        base::MakeUnique<std::vector<uint8_t>>(pair.second));
+    InFlightPropertyChange property_change(window, pair.first,
+                                           std::move(revert_value));
     InFlightChange* current_change =
         GetOldestInFlightChangeMatching(property_change);
-    if (current_change)
+    if (current_change) {
       current_change->SetRevertValueFrom(property_change);
-    else
-      window_private.LocalSetSharedProperty(pair.first, &(pair.second));
+    } else {
+      window->SetPropertyFromServer(pair.first, &pair.second);
+    }
   }
 
   // Top level windows should not have a parent.
   DCHECK_EQ(0u, data->parent_id);
 }
 
 void WindowTreeClient::OnWindowBoundsChanged(Id window_id,
                                              const gfx::Rect& old_bounds,
                                              const gfx::Rect& new_bounds) {
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
   InFlightBoundsChange new_change(window, new_bounds);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  WindowPrivate(window).LocalSetBounds(old_bounds, new_bounds);
+  window->SetBoundsFromServer(new_bounds);
 }
 
 void WindowTreeClient::OnClientAreaChanged(
     uint32_t window_id,
     const gfx::Insets& new_client_area,
     mojo::Array<gfx::Rect> new_additional_client_areas) {
+  // TODO: client area.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (window) {
     WindowPrivate(window).LocalSetClientArea(
         new_client_area,
         new_additional_client_areas.To<std::vector<gfx::Rect>>());
   }
+  */
 }
 
-void WindowTreeClient::OnTransientWindowAdded(
-    uint32_t window_id,
-    uint32_t transient_window_id) {
+void WindowTreeClient::OnTransientWindowAdded(uint32_t window_id,
+                                              uint32_t transient_window_id) {
+  // TODO: needs to route to StackingClient.
+  /*
   Window* window = GetWindowByServerId(window_id);
   Window* transient_window = GetWindowByServerId(transient_window_id);
   // window or transient_window or both may be null if a local delete occurs
   // with an in flight add from the server.
   if (window && transient_window)
     WindowPrivate(window).LocalAddTransientWindow(transient_window);
+  */
 }
 
-void WindowTreeClient::OnTransientWindowRemoved(
-    uint32_t window_id,
-    uint32_t transient_window_id) {
+void WindowTreeClient::OnTransientWindowRemoved(uint32_t window_id,
+                                                uint32_t transient_window_id) {
+  // TODO: needs to route to StackingClient.
+  /*
   Window* window = GetWindowByServerId(window_id);
   Window* transient_window = GetWindowByServerId(transient_window_id);
   // window or transient_window or both may be null if a local delete occurs
   // with an in flight delete from the server.
   if (window && transient_window)
     WindowPrivate(window).LocalRemoveTransientWindow(transient_window);
+  */
 }
 
 void WindowTreeClient::OnWindowHierarchyChanged(
     Id window_id,
     Id old_parent_id,
     Id new_parent_id,
-    mojo::Array<mojom::WindowDataPtr> windows) {
-  Window* initial_parent =
-      windows.size() ? GetWindowByServerId(windows[0]->parent_id) : NULL;
+    mojo::Array<ui::mojom::WindowDataPtr> windows) {
+  WindowMus* initial_parent =
+      windows.size() ? GetWindowByServerId(windows[0]->parent_id) : nullptr;
 
   const bool was_window_known = GetWindowByServerId(window_id) != nullptr;
 
   BuildWindowTree(windows, initial_parent);
 
   // If the window was not known, then BuildWindowTree() will have created it
   // and parented the window.
   if (!was_window_known)
     return;
 
-  Window* new_parent = GetWindowByServerId(new_parent_id);
-  Window* old_parent = GetWindowByServerId(old_parent_id);
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* new_parent = GetWindowByServerId(new_parent_id);
+  WindowMus* old_parent = GetWindowByServerId(old_parent_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (new_parent)
-    WindowPrivate(new_parent).LocalAddChild(window);
+    new_parent->AddChildFromServer(window);
   else
-    WindowPrivate(old_parent).LocalRemoveChild(window);
+    old_parent->RemoveChildFromServer(window);
 }
 
 void WindowTreeClient::OnWindowReordered(Id window_id,
-                                             Id relative_window_id,
-                                             mojom::OrderDirection direction) {
-  Window* window = GetWindowByServerId(window_id);
-  Window* relative_window = GetWindowByServerId(relative_window_id);
-  if (window && relative_window)
-    WindowPrivate(window).LocalReorder(relative_window, direction);
+                                         Id relative_window_id,
+                                         ui::mojom::OrderDirection direction) {
+  WindowMus* window = GetWindowByServerId(window_id);
+  WindowMus* relative_window = GetWindowByServerId(relative_window_id);
+  WindowMus* parent = WindowMus::Get(window->GetWindow()->parent());
+  if (window && relative_window && parent &&
+      parent == WindowMus::Get(relative_window->GetWindow()->parent())) {
+    parent->ReorderFromServer(window, relative_window, direction);
+  }
 }
 
 void WindowTreeClient::OnWindowDeleted(Id window_id) {
-  Window* window = GetWindowByServerId(window_id);
-  if (window)
-    WindowPrivate(window).LocalDestroy();
+  delete GetWindowByServerId(window_id)->GetWindow();
 }
 
 Window* WindowTreeClient::GetCaptureWindow() {
-  return capture_window_;
+  return capture_window_ ? capture_window_->GetWindow() : nullptr;
 }
 
-void WindowTreeClient::OnWindowVisibilityChanged(Id window_id,
-                                                     bool visible) {
-  Window* window = GetWindowByServerId(window_id);
+void WindowTreeClient::OnWindowVisibilityChanged(Id window_id, bool visible) {
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
   InFlightVisibleChange new_change(window, visible);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  WindowPrivate(window).LocalSetVisible(visible);
+  window->SetVisibleFromServer(visible);
 }
 
 void WindowTreeClient::OnWindowOpacityChanged(Id window_id,
-                                                  float old_opacity,
-                                                  float new_opacity) {
-  Window* window = GetWindowByServerId(window_id);
+                                              float old_opacity,
+                                              float new_opacity) {
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
   InFlightOpacityChange new_change(window, new_opacity);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  WindowPrivate(window).LocalSetOpacity(new_opacity);
+  window->SetOpacityFromServer(new_opacity);
 }
 
 void WindowTreeClient::OnWindowParentDrawnStateChanged(Id window_id,
-                                                           bool drawn) {
+                                                       bool drawn) {
+  // TODO: route to WindowTreeHost.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (window)
     WindowPrivate(window).LocalSetParentDrawn(drawn);
+  */
 }
 
 void WindowTreeClient::OnWindowSharedPropertyChanged(
     Id window_id,
     const mojo::String& name,
-    mojo::Array<uint8_t> new_data) {
-  Window* window = GetWindowByServerId(window_id);
+    mojo::Array<uint8_t> transport_data) {
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
-  InFlightPropertyChange new_change(window, name, new_data);
+  std::unique_ptr<std::vector<uint8_t>> data;
+  if (!transport_data.is_null()) {
+    data = base::MakeUnique<std::vector<uint8_t>>(
+        transport_data.To<std::vector<uint8_t>>());
+  }
+  InFlightPropertyChange new_change(window, name, std::move(data));
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  WindowPrivate(window).LocalSetSharedProperty(name, std::move(new_data));
+  if (!transport_data.is_null()) {
+    data = base::MakeUnique<std::vector<uint8_t>>(
+        transport_data.To<std::vector<uint8_t>>());
+  }
+  window->SetPropertyFromServer(name, data.get());
 }
 
 void WindowTreeClient::OnWindowInputEvent(uint32_t event_id,
                                           Id window_id,
                                           std::unique_ptr<ui::Event> event,
                                           bool matches_pointer_watcher) {
   DCHECK(event);
-  Window* window = GetWindowByServerId(window_id);  // May be null.
+
+  WindowMus* window = GetWindowByServerId(window_id);  // May be null.
+
+  if (event->IsKeyEvent()) {
+    DCHECK(!matches_pointer_watcher);  // PointerWatcher isn't for key events.
+    if (!window || !window->GetWindow()->GetHost()) {
+      tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
+      return;
+    }
+    InputMethodMus* input_method =
+        static_cast<WindowTreeHostMus*>(window->GetWindow()->GetHost())
+            ->input_method();
+    input_method->DispatchKeyEvent(event->AsKeyEvent(),
+                                   CreateEventResultCallback(event_id));
+    return;
+  }
 
   if (matches_pointer_watcher && has_pointer_watcher_) {
     DCHECK(event->IsPointerEvent());
-    delegate_->OnPointerEventObserved(*event->AsPointerEvent(), window);
+    delegate_->OnPointerEventObserved(*event->AsPointerEvent(),
+                                      window ? window->GetWindow() : nullptr);
   }
 
-  if (!window || !window->input_event_handler_) {
-    tree_->OnWindowInputEventAck(event_id, mojom::EventResult::UNHANDLED);
+  // TODO: deal with no window or host here. This could happen if during
+  // dispatch a window is deleted or moved. In either case we still need to
+  // dispatch. Most likely need the display id.
+  if (!window || !window->GetWindow()->GetHost()) {
+    tree_->OnWindowInputEventAck(event_id, ui::mojom::EventResult::UNHANDLED);
     return;
   }
 
-  std::unique_ptr<base::Callback<void(mojom::EventResult)>> ack_callback(
-      new base::Callback<void(mojom::EventResult)>(
-          base::Bind(&mojom::WindowTree::OnWindowInputEventAck,
-                     base::Unretained(tree_), event_id)));
-
+  EventAckHandler ack_handler(CreateEventResultCallback(event_id));
+  WindowTreeHostMus* host =
+      static_cast<WindowTreeHostMus*>(window->GetWindow()->GetHost());
   // TODO(moshayedi): crbug.com/617222. No need to convert to ui::MouseEvent or
   // ui::TouchEvent once we have proper support for pointer events.
   if (event->IsMousePointerEvent()) {
     if (event->type() == ui::ET_POINTER_WHEEL_CHANGED) {
-      window->input_event_handler_->OnWindowInputEvent(
-          window, ui::MouseWheelEvent(*event->AsPointerEvent()), &ack_callback);
+      ui::MouseWheelEvent mapped_event(*event->AsPointerEvent());
+      host->SendEventToProcessor(&mapped_event);
     } else {
-      window->input_event_handler_->OnWindowInputEvent(
-          window, ui::MouseEvent(*event->AsPointerEvent()), &ack_callback);
+      ui::MouseEvent mapped_event(*event->AsPointerEvent());
+      host->SendEventToProcessor(&mapped_event);
     }
   } else if (event->IsTouchPointerEvent()) {
-    window->input_event_handler_->OnWindowInputEvent(
-        window, ui::TouchEvent(*event->AsPointerEvent()), &ack_callback);
+    ui::TouchEvent mapped_event(*event->AsPointerEvent());
+    host->SendEventToProcessor(&mapped_event);
   } else {
-    window->input_event_handler_->OnWindowInputEvent(window, *event.get(),
-                                                     &ack_callback);
+    host->SendEventToProcessor(event.get());
   }
-
-  // The handler did not take ownership of the callback, so we send the ack,
-  // marking the event as not consumed.
-  if (ack_callback)
-    ack_callback->Run(mojom::EventResult::UNHANDLED);
+  ack_handler.set_handled(event->handled());
 }
 
 void WindowTreeClient::OnPointerEventObserved(std::unique_ptr<ui::Event> event,
                                               uint32_t window_id) {
   DCHECK(event);
   DCHECK(event->IsPointerEvent());
-  if (has_pointer_watcher_) {
-    Window* target_window = GetWindowByServerId(window_id);
-    delegate_->OnPointerEventObserved(*event->AsPointerEvent(), target_window);
-  }
+  if (!has_pointer_watcher_)
+    return;
+
+  WindowMus* target_window = GetWindowByServerId(window_id);
+  delegate_->OnPointerEventObserved(
+      *event->AsPointerEvent(),
+      target_window ? target_window->GetWindow() : nullptr);
 }
 
 void WindowTreeClient::OnWindowFocused(Id focused_window_id) {
-  Window* focused_window = GetWindowByServerId(focused_window_id);
+  WindowMus* focused_window = GetWindowByServerId(focused_window_id);
   InFlightFocusChange new_change(this, focused_window);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  LocalSetFocus(focused_window);
+  SetFocusFromServer(focused_window);
 }
 
 void WindowTreeClient::OnWindowPredefinedCursorChanged(
     Id window_id,
-    mojom::Cursor cursor) {
-  Window* window = GetWindowByServerId(window_id);
+    ui::mojom::Cursor cursor) {
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
 
   InFlightPredefinedCursorChange new_change(window, cursor);
   if (ApplyServerChangeToExistingInFlightChange(new_change))
     return;
 
-  WindowPrivate(window).LocalSetPredefinedCursor(cursor);
+  window->SetPredefinedCursorFromServer(cursor);
 }
 
 void WindowTreeClient::OnWindowSurfaceChanged(
     Id window_id,
     const cc::SurfaceId& surface_id,
     const cc::SurfaceSequence& surface_sequence,
     const gfx::Size& frame_size,
     float device_scale_factor) {
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window)
     return;
   std::unique_ptr<SurfaceInfo> surface_info(base::MakeUnique<SurfaceInfo>());
   surface_info->surface_id = surface_id;
   surface_info->surface_sequence = surface_sequence;
   surface_info->frame_size = frame_size;
   surface_info->device_scale_factor = device_scale_factor;
-  WindowPrivate(window).LocalSetSurfaceId(std::move(surface_info));
+  window->SetSurfaceIdFromServer(std::move(surface_info));
 }
 
 void WindowTreeClient::OnDragDropStart(
     mojo::Map<mojo::String, mojo::Array<uint8_t>> mime_data) {
   mime_drag_data_ = std::move(mime_data);
 }
 
 void WindowTreeClient::OnDragEnter(Id window_id,
                                    uint32_t key_state,
                                    const gfx::Point& position,
                                    uint32_t effect_bitmask,
                                    const OnDragEnterCallback& callback) {
+  // TODO: dnd.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (!window || !window->drop_target()) {
-    callback.Run(mojom::kDropEffectNone);
+    callback.Run(ui::mojom::kDropEffectNone);
     return;
   }
 
   if (!base::ContainsKey(drag_entered_windows_, window_id)) {
     window->drop_target()->OnDragDropStart(
         mime_drag_data_.To<std::map<std::string, std::vector<uint8_t>>>());
     drag_entered_windows_.insert(window_id);
   }
 
   uint32_t ret =
       window->drop_target()->OnDragEnter(key_state, position, effect_bitmask);
   callback.Run(ret);
+  */
 }
 
 void WindowTreeClient::OnDragOver(Id window_id,
                                   uint32_t key_state,
                                   const gfx::Point& position,
                                   uint32_t effect_bitmask,
                                   const OnDragOverCallback& callback) {
+  // TODO: dnd.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (!window || !window->drop_target()) {
-    callback.Run(mojom::kDropEffectNone);
+    callback.Run(ui::mojom::kDropEffectNone);
     return;
   }
 
   uint32_t ret =
       window->drop_target()->OnDragOver(key_state, position, effect_bitmask);
   callback.Run(ret);
+  */
 }
 
 void WindowTreeClient::OnDragLeave(Id window_id) {
+  // TODO: dnd.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (!window || !window->drop_target())
     return;
 
   window->drop_target()->OnDragLeave();
+  */
 }
 
 void WindowTreeClient::OnDragDropDone() {
+  // TODO: dnd.
+  /*
   for (Id id : drag_entered_windows_) {
     Window* window = GetWindowByServerId(id);
     if (!window || !window->drop_target())
       continue;
     window->drop_target()->OnDragDropDone();
   }
   drag_entered_windows_.clear();
+  */
 }
 
 void WindowTreeClient::OnCompleteDrop(Id window_id,
                                       uint32_t key_state,
                                       const gfx::Point& position,
                                       uint32_t effect_bitmask,
                                       const OnCompleteDropCallback& callback) {
+  // TODO: dnd.
+  /*
   Window* window = GetWindowByServerId(window_id);
   if (!window || !window->drop_target()) {
-    callback.Run(mojom::kDropEffectNone);
+    callback.Run(ui::mojom::kDropEffectNone);
     return;
   }
 
   uint32_t ret = window->drop_target()->OnCompleteDrop(key_state, position,
                                                        effect_bitmask);
   callback.Run(ret);
+  */
 }
 
 void WindowTreeClient::OnPerformDragDropCompleted(uint32_t change_id,
                                                   bool success,
                                                   uint32_t action_taken) {
+  // TODO: dnd.
+  /*
   if (current_drag_state_ && change_id == current_drag_state_->change_id) {
     current_drag_state_->completed_action = action_taken;
     OnChangeCompleted(change_id, success);
   }
+  */
 }
 
 void WindowTreeClient::OnChangeCompleted(uint32_t change_id, bool success) {
   std::unique_ptr<InFlightChange> change(std::move(in_flight_map_[change_id]));
   in_flight_map_.erase(change_id);
   if (!change)
     return;
 
   if (!success)
     change->ChangeFailed();
@@ skipping 17 matching lines @@
 
     current_drag_state_->on_finished.Run(success,
                                          current_drag_state_->completed_action);
     current_drag_state_.reset();
   }
 }
 
 void WindowTreeClient::GetWindowManager(
     mojo::AssociatedInterfaceRequest<WindowManager> internal) {
   window_manager_internal_.reset(
-      new mojo::AssociatedBinding<mojom::WindowManager>(this,
-                                                        std::move(internal)));
+      new mojo::AssociatedBinding<ui::mojom::WindowManager>(
+          this, std::move(internal)));
 }
 
 void WindowTreeClient::RequestClose(uint32_t window_id) {
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (!window || !IsRoot(window))
     return;
 
-  for (auto& observer : *WindowPrivate(window).observers())
-    observer.OnRequestClose(window);
+  window->GetWindow()->delegate()->OnRequestClose();
 }
 
 void WindowTreeClient::OnConnect(ClientSpecificId client_id) {
   client_id_ = client_id;
 }
 
 void WindowTreeClient::WmNewDisplayAdded(const display::Display& display,
-                                         mojom::WindowDataPtr root_data,
+                                         ui::mojom::WindowDataPtr root_data,
                                          bool parent_drawn) {
   WmNewDisplayAddedImpl(display, std::move(root_data), parent_drawn);
 }
 
 void WindowTreeClient::WmDisplayRemoved(int64_t display_id) {
   DCHECK(window_manager_delegate_);
-
+  // TODO: route to WindowTreeHost.
+  /*
   for (Window* root : roots_) {
     if (root->display_id() == display_id) {
       window_manager_delegate_->OnWmDisplayRemoved(root);
       return;
     }
   }
+  */
 }
 
 void WindowTreeClient::WmDisplayModified(const display::Display& display) {
   DCHECK(window_manager_delegate_);
+  // TODO(sky): this should likely route to WindowTreeHost.
   window_manager_delegate_->OnWmDisplayModified(display);
 }
 
 void WindowTreeClient::WmSetBounds(uint32_t change_id,
-                                       Id window_id,
-                                       const gfx::Rect& transit_bounds) {
-  Window* window = GetWindowByServerId(window_id);
+                                   Id window_id,
+                                   const gfx::Rect& transit_bounds) {
+  WindowMus* window = GetWindowByServerId(window_id);
   bool result = false;
   if (window) {
     DCHECK(window_manager_delegate_);
     gfx::Rect bounds = transit_bounds;
-    result = window_manager_delegate_->OnWmSetBounds(window, &bounds);
+    // TODO: this needs to trigger scheduling a bounds change on |window|.
+    result =
+        window_manager_delegate_->OnWmSetBounds(window->GetWindow(), &bounds);
     if (result) {
       // If the resulting bounds differ return false. Returning false ensures
       // the client applies the bounds we set below.
       result = bounds == transit_bounds;
-      window->SetBounds(bounds);
+      window->SetBoundsFromServer(bounds);
     }
   }
   if (window_manager_internal_client_)
     window_manager_internal_client_->WmResponse(change_id, result);
 }
 
 void WindowTreeClient::WmSetProperty(uint32_t change_id,
                                      Id window_id,
                                      const mojo::String& name,
                                      mojo::Array<uint8_t> transit_data) {
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   bool result = false;
   if (window) {
+    // TODO: map properties.
     DCHECK(window_manager_delegate_);
     std::unique_ptr<std::vector<uint8_t>> data;
     if (!transit_data.is_null()) {
       data.reset(
           new std::vector<uint8_t>(transit_data.To<std::vector<uint8_t>>()));
     }
-    result = window_manager_delegate_->OnWmSetProperty(window, name, &data);
+    result = window_manager_delegate_->OnWmSetProperty(window->GetWindow(),
+                                                       name, &data);
     if (result) {
-      // If the resulting bounds differ return false. Returning false ensures
-      // the client applies the bounds we set below.
-      window->SetSharedPropertyInternal(name, data.get());
+      delegate_->GetPropertyConverter()->SetPropertyFromTransportValue(
+          window->GetWindow(), name, data.get());
     }
   }
   if (window_manager_internal_client_)
     window_manager_internal_client_->WmResponse(change_id, result);
 }
 
 void WindowTreeClient::WmCreateTopLevelWindow(
     uint32_t change_id,
     ClientSpecificId requesting_client_id,
     mojo::Map<mojo::String, mojo::Array<uint8_t>> transport_properties) {
   std::map<std::string, std::vector<uint8_t>> properties =
       transport_properties.To<std::map<std::string, std::vector<uint8_t>>>();
   Window* window =
       window_manager_delegate_->OnWmCreateTopLevelWindow(&properties);
   embedded_windows_[requesting_client_id].insert(window);
   if (window_manager_internal_client_) {
     window_manager_internal_client_->OnWmCreatedTopLevelWindow(
-        change_id, server_id(window));
+        change_id, WindowMus::Get(window)->server_id());
   }
 }
 
 void WindowTreeClient::WmClientJankinessChanged(ClientSpecificId client_id,
                                                 bool janky) {
   if (window_manager_delegate_) {
     auto it = embedded_windows_.find(client_id);
     CHECK(it != embedded_windows_.end());
     window_manager_delegate_->OnWmClientJankinessChanged(
         embedded_windows_[client_id], janky);
   }
 }
 
 void WindowTreeClient::WmPerformMoveLoop(uint32_t change_id,
                                          Id window_id,
-                                         mojom::MoveLoopSource source,
+                                         ui::mojom::MoveLoopSource source,
                                          const gfx::Point& cursor_location) {
   if (!window_manager_delegate_ || current_wm_move_loop_change_ != 0) {
     OnWmMoveLoopCompleted(change_id, false);
     return;
   }
 
   current_wm_move_loop_change_ = change_id;
   current_wm_move_loop_window_id_ = window_id;
-  Window* window = GetWindowByServerId(window_id);
+  WindowMus* window = GetWindowByServerId(window_id);
   if (window) {
     window_manager_delegate_->OnWmPerformMoveLoop(
-        window, source, cursor_location,
+        window->GetWindow(), source, cursor_location,
         base::Bind(&WindowTreeClient::OnWmMoveLoopCompleted,
                    weak_factory_.GetWeakPtr(), change_id));
   } else {
     OnWmMoveLoopCompleted(change_id, false);
   }
 }
 
 void WindowTreeClient::WmCancelMoveLoop(uint32_t change_id) {
   if (!window_manager_delegate_ || change_id != current_wm_move_loop_change_)
     return;
 
-  Window* window = GetWindowByServerId(current_wm_move_loop_window_id_);
+  WindowMus* window = GetWindowByServerId(current_wm_move_loop_window_id_);
   if (window)
-    window_manager_delegate_->OnWmCancelMoveLoop(window);
+    window_manager_delegate_->OnWmCancelMoveLoop(window->GetWindow());
 }
 
 void WindowTreeClient::OnAccelerator(uint32_t ack_id,
                                      uint32_t accelerator_id,
                                      std::unique_ptr<ui::Event> event) {
   DCHECK(event);
-  const mojom::EventResult result =
+  const ui::mojom::EventResult result =
       window_manager_delegate_->OnAccelerator(accelerator_id, *event.get());
   if (ack_id && window_manager_internal_client_)
     window_manager_internal_client_->OnAcceleratorAck(ack_id, result);
 }
 
 void WindowTreeClient::SetFrameDecorationValues(
-    mojom::FrameDecorationValuesPtr values) {
+    ui::mojom::FrameDecorationValuesPtr values) {
   if (window_manager_internal_client_) {
     window_manager_internal_client_->WmSetFrameDecorationValues(
         std::move(values));
   }
 }
 
 void WindowTreeClient::SetNonClientCursor(Window* window,
                                           ui::mojom::Cursor cursor_id) {
-  window_manager_internal_client_->WmSetNonClientCursor(server_id(window),
-                                                        cursor_id);
+  window_manager_internal_client_->WmSetNonClientCursor(
+      WindowMus::Get(window)->server_id(), cursor_id);
 }
 
 void WindowTreeClient::AddAccelerator(
     uint32_t id,
-    mojom::EventMatcherPtr event_matcher,
+    ui::mojom::EventMatcherPtr event_matcher,
     const base::Callback<void(bool)>& callback) {
   if (window_manager_internal_client_) {
     window_manager_internal_client_->AddAccelerator(
         id, std::move(event_matcher), callback);
   }
 }
 
 void WindowTreeClient::RemoveAccelerator(uint32_t id) {
   if (window_manager_internal_client_) {
     window_manager_internal_client_->RemoveAccelerator(id);
   }
 }
 
 void WindowTreeClient::AddActivationParent(Window* window) {
-  if (window_manager_internal_client_)
-    window_manager_internal_client_->AddActivationParent(server_id(window));
+  if (window_manager_internal_client_) {
+    window_manager_internal_client_->AddActivationParent(
+        WindowMus::Get(window)->server_id());
+  }
 }
 
 void WindowTreeClient::RemoveActivationParent(Window* window) {
-  if (window_manager_internal_client_)
-    window_manager_internal_client_->RemoveActivationParent(server_id(window));
+  if (window_manager_internal_client_) {
+    window_manager_internal_client_->RemoveActivationParent(
+        WindowMus::Get(window)->server_id());
+  }
 }
 
 void WindowTreeClient::ActivateNextWindow() {
   if (window_manager_internal_client_)
     window_manager_internal_client_->ActivateNextWindow();
 }
 
 void WindowTreeClient::SetUnderlaySurfaceOffsetAndExtendedHitArea(
     Window* window,
     const gfx::Vector2d& offset,
     const gfx::Insets& hit_area) {
   if (window_manager_internal_client_) {
     window_manager_internal_client_->SetUnderlaySurfaceOffsetAndExtendedHitArea(
-        server_id(window), offset.x(), offset.y(), hit_area);
+        WindowMus::Get(window)->server_id(), offset.x(), offset.y(), hit_area);
   }
 }
 
-}  // namespace ui
+void WindowTreeClient::OnWindowFocused(Window* gained_focus,
+                                       Window* lost_focus) {
+  WindowMus* gained_focus_mus = WindowMus::Get(gained_focus);
+  if (setting_focus_ && gained_focus_mus == window_setting_focus_to_) {
+    focused_window_ = gained_focus_mus;
+    return;
+  }
+
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<InFlightFocusChange>(this, focused_window_));
+  focused_window_ = gained_focus_mus;
+  tree_->SetFocus(change_id, focused_window_ ? focused_window_->server_id()
+                                             : kInvalidServerId);
+}
+
+void WindowTreeClient::OnCaptureChanged(Window* lost_capture,
+                                        Window* gained_capture) {
+  WindowMus* gained_capture_mus = WindowMus::Get(gained_capture);
+  if (setting_capture_ && gained_capture_mus == window_setting_capture_to_) {
+    capture_window_ = gained_capture_mus;
+    return;
+  }
+
+  const uint32_t change_id = ScheduleInFlightChange(
+      base::MakeUnique<InFlightCaptureChange>(this, capture_window_));
+  WindowMus* old_capture_window = capture_window_;
+  capture_window_ = gained_capture_mus;
+  if (capture_window_)
+    tree_->SetCapture(change_id, capture_window_->server_id());
+  else
+    tree_->ReleaseCapture(change_id, old_capture_window->server_id());
+}
+
+}  // namespace aura