Fixes to WindowTreeHostMus

ui/aura/mus/window_mus.h

Index: ui/aura/mus/window_mus.h
diff --git a/ui/aura/mus/window_mus.h b/ui/aura/mus/window_mus.h
index d9657966e64f4bcdf55f5ddd7b7fb66f5a1ed53c..c39baa2dd0f68671d67e8515565f3b55160704a8 100644
--- a/ui/aura/mus/window_mus.h
+++ b/ui/aura/mus/window_mus.h
@@ -16,6 +16,7 @@
 
 namespace gfx {
 class Rect;
+class Vector2d;
 }
 
 namespace ui {
@@ -30,6 +31,11 @@ struct SurfaceInfo;
 class Window;
 class WindowTreeClient;
 
+// See PrepareForServerBoundsChange() for details on this.
+struct AURA_EXPORT WindowMusChangeData {
+  virtual ~WindowMusChangeData() {}
+};
+
 // WindowMus defines the interface used by WindowTreeClient to modify
 // the underlying Window. It's defined as a separate interface to make it clear
 // that any changes that WindowTreeClient makes must be propagated through
@@ -72,6 +78,16 @@ class AURA_EXPORT WindowMus {
   virtual void SetSurfaceIdFromServer(
       std::unique_ptr<SurfaceInfo> surface_info) = 0;
 
+  // Called in the rare case when WindowTreeClient needs to state and can't go

[sadrul, 2016/10/27 20:26:17]

"...needs to +change state"?

[sky, 2016/10/27 22:15:04]

Done.

+  // through one of the SetFooFromServer() functions above. Generally because
+  // it needs to call another function that as a side effect changes the window.
+  // Once the call to the underlying window has completed the returned object
+  // should be destroyed.
+  virtual std::unique_ptr<WindowMusChangeData> PrepareForServerBoundsChange(
+      const gfx::Rect& bounds) = 0;
+  virtual std::unique_ptr<WindowMusChangeData> PrepareForServerVisibilityChange(

[sadrul, 2016/10/27 20:26:17]

It doesn't look like the visibility one is being used yet.

[sky, 2016/10/27 22:15:04]

It should have. I added test coverage, which uncovered a couple of problems that
I've fixed here.

+      bool value) = 0;
+
   virtual void NotifyEmbeddedAppDisconnected() = 0;
 
  private: