exo: WMHelperMus: Hook up event handlers for mus+ash

components/exo/wm_helper_mus.cc

Index: components/exo/wm_helper_mus.cc
diff --git a/components/exo/wm_helper_mus.cc b/components/exo/wm_helper_mus.cc
index 46400317b5ee934f4ded13a4e589dcac927debbd..068baf569c4c8b1dd42ec7f96687bc041b0d9b51 100644
--- a/components/exo/wm_helper_mus.cc
+++ b/components/exo/wm_helper_mus.cc
@@ -7,6 +7,8 @@
 #include "ash/common/display/display_info.h"
 #include "services/ui/public/cpp/window_tree_client.h"
 #include "ui/aura/client/focus_client.h"
+#include "ui/aura/env.h"
+#include "ui/aura/window.h"
 #include "ui/views/mus/native_widget_mus.h"
 #include "ui/views/mus/window_manager_connection.h"
 #include "ui/views/widget/widget.h"
@@ -27,24 +29,53 @@ aura::Window* GetToplevelAuraWindow(ui::Window* window) {
 }  // namespace
 
 ////////////////////////////////////////////////////////////////////////////////
+// WMHelperMus::EventForwarder:
+
+class WMHelperMus::EventForwarder : public ui::EventHandler {
+ public:
+  explicit EventForwarder(ui::EventHandlerList* event_handlers)
+      : event_handlers_(event_handlers) {}
+  ~EventForwarder() override {}
+
+  // Overriden from ui::EventHandler:
+  void OnEvent(ui::Event* event) override;
+
+ private:
+  const ui::EventHandlerList* event_handlers_;
+
+  DISALLOW_COPY_AND_ASSIGN(EventForwarder);
+};
+
+void WMHelperMus::EventForwarder::OnEvent(ui::Event* event) {
+  for (ui::EventHandler* handler : *event_handlers_) {
+    if (event->stopped_propagation())
+      break;
+    handler->OnEvent(event);
+  }
+}
+////////////////////////////////////////////////////////////////////////////////
 // WMHelperMus, public:
 
 WMHelperMus::WMHelperMus()
-    : active_window_(WMHelperMus::GetActiveWindow()),
+    : pre_target_event_forwarder_(new EventForwarder(&pre_target_list_)),
+      post_target_event_forwarder_(new EventForwarder(&post_target_list_)),
+      active_window_(WMHelperMus::GetActiveWindow()),
       focused_window_(WMHelperMus::GetFocusedWindow()) {
   views::WindowManagerConnection::Get()->client()->AddObserver(this);
+  aura::Env::GetInstance()->AddObserver(this);
 }
 
 WMHelperMus::~WMHelperMus() {
   views::WindowManagerConnection::Get()->client()->RemoveObserver(this);
+  aura::Env::GetInstance()->RemoveObserver(this);
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // WMHelperMus, private:
 
 const ash::DisplayInfo WMHelperMus::GetDisplayInfo(int64_t display_id) const {
-  NOTIMPLEMENTED();
-  return ash::DisplayInfo();
+  // TODO(penghuang): Return real display info when it is supported in mus.
+  return ash::DisplayInfo(display_id, "", false);
 }
 
 aura::Window* WMHelperMus::GetContainer(int container_id) {
@@ -73,23 +104,29 @@ ui::CursorSetType WMHelperMus::GetCursorSet() const {
 }
 
 void WMHelperMus::AddPreTargetHandler(ui::EventHandler* handler) {
-  NOTIMPLEMENTED();
+  pre_target_list_.push_back(handler);
 }
 
 void WMHelperMus::PrependPreTargetHandler(ui::EventHandler* handler) {
-  NOTIMPLEMENTED();
+  pre_target_list_.insert(pre_target_list_.begin(), handler);
 }
 
 void WMHelperMus::RemovePreTargetHandler(ui::EventHandler* handler) {
-  NOTIMPLEMENTED();
+  auto it =
+      std::find(pre_target_list_.begin(), pre_target_list_.end(), handler);
+  if (it != pre_target_list_.end())
+    pre_target_list_.erase(it);
 }
 
 void WMHelperMus::AddPostTargetHandler(ui::EventHandler* handler) {
-  NOTIMPLEMENTED();
+  post_target_list_.push_back(handler);
 }
 
 void WMHelperMus::RemovePostTargetHandler(ui::EventHandler* handler) {
-  NOTIMPLEMENTED();
+  auto it =
+      std::find(post_target_list_.begin(), post_target_list_.end(), handler);
+  if (it != post_target_list_.end())
+    post_target_list_.erase(it);
 }
 
 bool WMHelperMus::IsMaximizeModeWindowManagerEnabled() const {
@@ -97,6 +134,12 @@ bool WMHelperMus::IsMaximizeModeWindowManagerEnabled() const {
   return false;
 }
 
+void WMHelperMus::OnHostInitialized(aura::WindowTreeHost* host) {
+  aura::Window* root_window = host->window();
+  root_window->AddPreTargetHandler(pre_target_event_forwarder_.get());
+  root_window->AddPostTargetHandler(post_target_event_forwarder_.get());
+}
+
 void WMHelperMus::OnWindowTreeFocusChanged(ui::Window* gained_focus,
                                            ui::Window* lost_focus) {
   aura::Window* gained_active =