aura-mus: Implement Deactivate().

ui/views/mus/desktop_window_tree_host_mus.cc

Index: ui/views/mus/desktop_window_tree_host_mus.cc
diff --git a/ui/views/mus/desktop_window_tree_host_mus.cc b/ui/views/mus/desktop_window_tree_host_mus.cc
index 87571a76b30d3abaca869fa53a465775f39b287a..41f0eba497535e5cd31197084b30e7f6d415649a 100644
--- a/ui/views/mus/desktop_window_tree_host_mus.cc
+++ b/ui/views/mus/desktop_window_tree_host_mus.cc
@@ -181,6 +181,7 @@ DesktopWindowTreeHostMus::DesktopWindowTreeHostMus(
       close_widget_factory_(this) {
   aura::Env::GetInstance()->AddObserver(this);
   MusClient::Get()->AddObserver(this);
+  native_widget_delegate_->AsWidget()->AddObserver(this);
   // DesktopNativeWidgetAura registers the association between |content_window_|
   // and Widget, but code may also want to go from the root (window()) to the
   // Widget. This call enables that.
@@ -195,6 +196,7 @@ DesktopWindowTreeHostMus::~DesktopWindowTreeHostMus() {
   // the cursor-client needs to be unset on the root-window before
   // |cursor_manager_| is destroyed.
   aura::client::SetCursorClient(window(), nullptr);
+  native_widget_delegate_->AsWidget()->RemoveObserver(this);
   MusClient::Get()->RemoveObserver(this);
   aura::Env::GetInstance()->RemoveObserver(this);
   desktop_native_widget_aura_->OnDesktopWindowTreeHostDestroyed(this);
@@ -280,6 +282,13 @@ void DesktopWindowTreeHostMus::OnNativeWidgetCreated(
   native_widget_delegate_->OnNativeWidgetCreated(true);
 }
 
+void DesktopWindowTreeHostMus::OnNativeWidgetActivationChanged(bool active) {
+  // In Mus, when our aura Window receives an activation signal, it can be
+  // because of remote messages. We need to forward that to Widget so that
+  // Widget can notify everyone listening for that signal.
+  native_widget_delegate_->OnNativeWidgetActivationChanged(active);
+}
+
 void DesktopWindowTreeHostMus::OnWidgetInitDone() {
   // Because of construction order it's possible the bounds have changed before
   // the NonClientView was created, which means we may not have sent the
@@ -492,9 +501,8 @@ void DesktopWindowTreeHostMus::Activate() {
 }
 
 void DesktopWindowTreeHostMus::Deactivate() {
-  // TODO: Deactivate() means focus next window, that needs to go to mus.
-  // http://crbug.com/663618.
-  NOTIMPLEMENTED();
+  if (is_active_)
+    DeactivateWindow();
 }
 
 bool DesktopWindowTreeHostMus::IsActive() const {
@@ -669,6 +677,11 @@ void DesktopWindowTreeHostMus::OnWindowManagerFrameValuesChanged() {
   SendHitTestMaskToServer();
 }
 
+void DesktopWindowTreeHostMus::OnWidgetActivationChanged(Widget* widget,
+                                                         bool active) {
+  is_active_ = active;

[Elliot Glaysher, 2017/01/12 23:20:37]

I have readded this. We discussed setting |is_active_| in
DesktopWindowTreeHostMus::OnNativeWidgetActivationChanged() instead of in a
WidgetObserver method. However, this breaks focus, whether I set |is_active_|
before or after the call to Widget::OnNativeWidgetActivationChanged(). Moving
setting |is_active_|  back here fixes everything.

I'm fairly confused as to why this is required and (theoretically) they should
be equivalent. They obviously aren't though. The only thing that I can think of
is that there are places in the activation code path which rely on the old
widget not to report being active before some signal, and to report the opposite
afterwards.

[sky, 2017/01/13 00:01:19]

Can you add a TODO to track down why? It would be good to know.

+}
+
 void DesktopWindowTreeHostMus::ShowImpl() {
   native_widget_delegate_->OnNativeWidgetVisibilityChanging(true);
   // Using ui::SHOW_STATE_NORMAL matches that of DesktopWindowTreeHostX11.
@@ -711,10 +724,8 @@ void DesktopWindowTreeHostMus::OnActiveFocusClientChanged(
     aura::client::FocusClient* focus_client,
     aura::Window* window) {
   if (window == this->window()) {
-    is_active_ = true;
     desktop_native_widget_aura_->HandleActivationChanged(true);
   } else if (is_active_) {
-    is_active_ = false;
     desktop_native_widget_aura_->HandleActivationChanged(false);
   }
 }