mus: Re-wire how a bounds change request works.

. A client can request to change the bounds of a window it doesn't own (e.g.
  a window created by the window-manager). The client is notified if the
  change request is rejected.

. The window-server routes bounds-change requests from clients through the
  window-manager for windows created by the WM.

. Instead of NativeWidgetMus directly requesting the bounds update on the
  mus::Window, it goes through WindowTreeHostMus, which sends the request to
  mus to change the size of the mus::Window.

. Instead of WindowTreeHostMus directly changing the bounds of the root-window,
  it lets the base WindowTreeHost implementation take care of updating the
  root-window's bounds when necessary (e.g. when the host is resized etc.)

BUG=none

Review URL: https://codereview.chromium.org/1414333009

Cr-Commit-Position: refs/heads/master@{#357903}

3 files changed, 15 insertions, 12 deletions

diff --git a/ui/views/mus/native_widget_mus.cc b/ui/views/mus/native_widget_mus.cc
index b035a18..f9b43d3 100644
--- a/ui/views/mus/native_widget_mus.cc
+++ b/ui/views/mus/native_widget_mus.cc
@@ -249,11 +249,12 @@ gfx::Rect NativeWidgetMus::GetRestoredBounds() const {
 }
 
 void NativeWidgetMus::SetBounds(const gfx::Rect& bounds) {
-  window_->RequestBoundsChange(bounds);
+  window_tree_host_->SetBounds(bounds);
 }
 
 void NativeWidgetMus::SetSize(const gfx::Size& size) {
-  window_->RequestBoundsChange(gfx::Rect(window_->bounds().size()));
+  gfx::Rect bounds = window_tree_host_->GetBounds();
+  SetBounds(gfx::Rect(bounds.origin(), size));
 }
 
 void NativeWidgetMus::StackAbove(gfx::NativeView native_view) {
diff --git a/ui/views/mus/window_tree_host_mus.cc b/ui/views/mus/window_tree_host_mus.cc
index fd7e1f1..f4edd4c 100644
--- a/ui/views/mus/window_tree_host_mus.cc
+++ b/ui/views/mus/window_tree_host_mus.cc
@@ -68,6 +68,14 @@ void WindowTreeHostMus::SetShowState(mus::mojom::ShowState show_state) {
 ////////////////////////////////////////////////////////////////////////////////
 // WindowTreeHostMus, aura::WindowTreeHost implementation:
 
+gfx::Rect WindowTreeHostMus::GetBounds() const {
+  return mus_window_->bounds();
+}
+
+void WindowTreeHostMus::SetBounds(const gfx::Rect& bounds) {
+  mus_window_->SetBounds(bounds);
+}
+
 ui::EventSource* WindowTreeHostMus::GetEventSource() {
   return this;
 }
@@ -86,14 +94,6 @@ void WindowTreeHostMus::HideImpl() {
   window()->Hide();
 }
 
-gfx::Rect WindowTreeHostMus::GetBounds() const {
-  return mus_window_->bounds();
-}
-
-void WindowTreeHostMus::SetBounds(const gfx::Rect& bounds) {
-  window()->SetBounds(gfx::Rect(bounds.size()));
-}
-
 gfx::Point WindowTreeHostMus::GetLocationOnNativeScreen() const {
   return gfx::Point(0, 0);
 }
diff --git a/ui/views/mus/window_tree_host_mus.h b/ui/views/mus/window_tree_host_mus.h
index 6f4d9ad..258ab95 100644
--- a/ui/views/mus/window_tree_host_mus.h
+++ b/ui/views/mus/window_tree_host_mus.h
@@ -44,14 +44,16 @@ class WindowTreeHostMus : public aura::WindowTreeHost,
     return ui::EventSource::SendEventToProcessor(event);
   }
 
+  // WindowTreeHost:
+  gfx::Rect GetBounds() const override;
+  void SetBounds(const gfx::Rect& bounds) override;
+
  private:
   // WindowTreeHost:
   ui::EventSource* GetEventSource() override;
   gfx::AcceleratedWidget GetAcceleratedWidget() override;
   void ShowImpl() override;
   void HideImpl() override;
-  gfx::Rect GetBounds() const override;
-  void SetBounds(const gfx::Rect& bounds) override;
   gfx::Point GetLocationOnNativeScreen() const override;
   void SetCapture() override;
   void ReleaseCapture() override;