Add the beginning of a simple window manager that we'll support on Windows.

mash/simple_wm/simple_wm.cc

+// Copyright 2016 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 "mash/simple_wm/simple_wm.h"
+
+#include "ui/aura/client/aura_constants.h"
+#include "ui/display/screen_base.h"
+#include "ui/gfx/canvas.h"
+#include "ui/gfx/geometry/mojo/geometry.mojom.h"
+#include "ui/views/controls/label.h"
+#include "ui/views/mus/aura_init.h"
+#include "ui/views/mus/mus_client.h"
+#include "ui/views/widget/native_widget_aura.h"
+#include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_delegate.h"
+
+namespace simple_wm {
+
+namespace {
+
+const int kNonClientTopHeight = 30;
+const int kNonClientSize = 5;
+
+}  // namespace
+
+class SimpleWM::FrameView : public views::WidgetDelegateView,
+                            public aura::WindowObserver {
+ public:
+  explicit FrameView(aura::Window* client_window)
+      : client_window_(client_window),
+        title_(new views::Label(L"(default)")) {
+    client_window_->AddObserver(this);
+    title_->SetHorizontalAlignment(gfx::ALIGN_LEFT);
+    AddChildView(title_);
+  }
+  ~FrameView() override {}
+
+ private:
+  // views::WidgetDelegateView:
+  void OnPaint(gfx::Canvas* canvas) override {
+    canvas->FillRect(GetLocalBounds(), SK_ColorRED);
+  }
+  void Layout() override {
+    gfx::Size ps = title_->GetPreferredSize();
+    gfx::Rect title_bounds = GetLocalBounds();
+    int v_offset = (kNonClientTopHeight - ps.height()) / 2;
+    title_bounds.SetRect(kNonClientSize, v_offset,
+                         title_bounds.width() - 2 * kNonClientSize,
+                         ps.height());
+    title_->SetBoundsRect(title_bounds);
+
+    client_window_->SetBounds(GetLocalBounds());

[sky, 2016/11/30 21:25:46]

Don't you want to offset the bounds by the title?
Generally you should use OnWmSetClientArea here, but as this is a simple wm it
doesn't really matter.

+  }
+
+  // aura::WindowObserver:
+  void OnWindowPropertyChanged(aura::Window* window, const void* key,
+                               intptr_t old) override {
+    if (key == aura::client::kTitleKey) {
+      base::string16 title = *window->GetProperty(aura::client::kTitleKey);
+      title_->SetText(title);
+    }
+  }
+
+  aura::Window* client_window_;
+  views::Label* title_;
+
+  DISALLOW_COPY_AND_ASSIGN(FrameView);
+};
+
+SimpleWM::SimpleWM() {}
+
+SimpleWM::~SimpleWM() {
+  // WindowTreeHost uses state from WindowTreeClient, so destroy it first.
+  window_tree_host_.reset();
+
+  // WindowTreeClient destruction may callback to us.
+  window_tree_client_.reset();
+
+  gpu_service_.reset();
+
+  display::Screen::SetScreenInstance(nullptr);
+}
+
+void SimpleWM::OnStart() {
+  CHECK(!started_);
+  started_ = true;
+  screen_ = base::MakeUnique<display::ScreenBase>();
+  display::Screen::SetScreenInstance(screen_.get());
+  aura_init_ = base::MakeUnique<views::AuraInit>(
+      context()->connector(), context()->identity(), "views_mus_resources.pak",
+      std::string(), nullptr, views::AuraInit::Mode::AURA_MUS_WINDOW_MANAGER);
+  gpu_service_ = ui::GpuService::Create(context()->connector(), nullptr);
+  compositor_context_factory_ =
+      base::MakeUnique<aura::MusContextFactory>(gpu_service_.get());
+  aura::Env::GetInstance()->set_context_factory(
+      compositor_context_factory_.get());
+  window_tree_client_ = base::MakeUnique<aura::WindowTreeClient>(
+      context()->connector(), this, this);
+  aura::Env::GetInstance()->SetWindowTreeClient(window_tree_client_.get());
+  window_tree_client_->ConnectAsWindowManager();
+}
+
+bool SimpleWM::OnConnect(
+    const service_manager::ServiceInfo& remote_info,
+    service_manager::InterfaceRegistry* registry) {
+  return true;
+}
+
+void SimpleWM::OnEmbed(
+    std::unique_ptr<aura::WindowTreeHostMus> window_tree_host) {
+  // WindowTreeClients configured as the window manager should never get
+  // OnEmbed().
+  NOTREACHED();
+}
+
+void SimpleWM::OnLostConnection(aura::WindowTreeClient* client) {
+  window_tree_host_.reset();
+  window_tree_client_.reset();
+}
+
+void SimpleWM::OnEmbedRootDestroyed(aura::Window* root) {
+  // WindowTreeClients configured as the window manager should never get
+  // OnEmbedRootDestroyed().
+  NOTREACHED();
+}
+
+void SimpleWM::OnPointerEventObserved(const ui::PointerEvent& event,
+                                      aura::Window* target) {
+  // Don't care.
+}
+
+aura::client::CaptureClient* SimpleWM::GetCaptureClient() {
+  return wm_state_.capture_controller();
+}
+
+aura::PropertyConverter* SimpleWM::GetPropertyConverter() {
+  return &property_converter_;
+}
+
+void SimpleWM::SetWindowManagerClient(
+    aura::WindowManagerClient* client) {
+  window_manager_client_ = client;
+}
+
+bool SimpleWM::OnWmSetBounds(aura::Window* window, gfx::Rect* bounds) {
+  FrameView* frame_view = GetFrameViewForClientWindow(window);
+  frame_view->GetWidget()->SetBounds(*bounds);
+  return true;
+}
+
+bool SimpleWM::OnWmSetProperty(
+    aura::Window* window,
+    const std::string& name,
+    std::unique_ptr<std::vector<uint8_t>>* new_data) {
+  return true;
+}
+
+aura::Window* SimpleWM::OnWmCreateTopLevelWindow(
+    ui::mojom::WindowType window_type,
+    std::map<std::string, std::vector<uint8_t>>* properties) {
+  aura::Window* client_window = new aura::Window(nullptr);
+  SetWindowType(client_window, window_type);
+  client_window->Init(ui::LAYER_NOT_DRAWN);
+
+  views::Widget* frame_widget = new views::Widget;
+  views::NativeWidgetAura* frame_native_widget =
+      new views::NativeWidgetAura(frame_widget);

[sky, 2016/11/30 21:25:46]

You should pass in an additional parameter of true here to indicate the
NativeWidgetAura is for the window manager.

+  views::Widget::InitParams params(views::Widget::InitParams::TYPE_CONTROL);

[sky, 2016/11/30 21:25:46]

Don't you want TYPE_WINDOW?

+  FrameView* frame_view = new FrameView(client_window);
+  params.delegate = frame_view;
+  params.native_widget = frame_native_widget;
+  params.parent = root_;
+  params.bounds = gfx::Rect(10, 10, 500, 500);
+  frame_widget->Init(params);
+  frame_widget->Show();
+
+  frame_widget->GetNativeWindow()->AddChild(client_window);
+
+  client_window_to_frame_view_[client_window] = frame_view;
+  // TODO(beng): probably need to observe client_window from now on so we can
+  // clean up this map.
+
+  return client_window;
+}
+
+void SimpleWM::OnWmClientJankinessChanged(
+    const std::set<aura::Window*>& client_windows,
+    bool janky) {
+  // Don't care.
+}
+
+void SimpleWM::OnWmWillCreateDisplay(const display::Display& display) {
+  screen_->display_list().AddDisplay(display,
+                                     display::DisplayList::Type::PRIMARY);
+}
+
+void SimpleWM::OnWmNewDisplay(
+    std::unique_ptr<aura::WindowTreeHostMus> window_tree_host,
+    const display::Display& display) {
+  // Only handles a single root.
+  DCHECK(!root_);
+  window_tree_host_ = std::move(window_tree_host);
+  window_tree_host_->InitCompositor();
+  root_ = window_tree_host_->window();
+  DCHECK(window_manager_client_);
+  window_manager_client_->AddActivationParent(root_);
+  ui::mojom::FrameDecorationValuesPtr frame_decoration_values =
+      ui::mojom::FrameDecorationValues::New();
+  frame_decoration_values->normal_client_area_insets.Set(
+      kNonClientTopHeight, kNonClientSize, kNonClientSize, kNonClientSize);
+  frame_decoration_values->max_title_bar_button_width = 0;
+  window_manager_client_->SetFrameDecorationValues(
+      std::move(frame_decoration_values));
+  aura::client::SetFocusClient(root_, &focus_client_);
+}
+
+void SimpleWM::OnWmDisplayRemoved(
+    aura::WindowTreeHostMus* window_tree_host) {
+  DCHECK_EQ(window_tree_host, window_tree_host_.get());
+  root_ = nullptr;
+  window_tree_host_.reset();
+}
+
+void SimpleWM::OnWmDisplayModified(const display::Display& display) {}
+
+void SimpleWM::OnWmPerformMoveLoop(
+    aura::Window* window,
+    ui::mojom::MoveLoopSource source,
+    const gfx::Point& cursor_location,
+    const base::Callback<void(bool)>& on_done) {
+  // Don't care.
+}
+
+void SimpleWM::OnWmCancelMoveLoop(aura::Window* window) {}
+
+void SimpleWM::OnWmSetClientArea(
+    aura::Window* window,
+    const gfx::Insets& insets,
+    const std::vector<gfx::Rect>& additional_client_areas) {}
+
+SimpleWM::FrameView* SimpleWM::GetFrameViewForClientWindow(
+    aura::Window* client_window) {
+  auto it = client_window_to_frame_view_.find(client_window);
+  return it != client_window_to_frame_view_.end() ? it->second : nullptr;
+}
+
+}  // namespace simple_wm
+