aura: Some changes in Window and Desktop.

ui/aura/desktop.cc

Index: ui/aura/desktop.cc
diff --git a/ui/aura/desktop.cc b/ui/aura/desktop.cc
index 565628e5139741a1a1e3a37d23dfaed8377fe132..58e0f66f0accbf9350b0503ad2d35c12e2ba8d5a 100644
--- a/ui/aura/desktop.cc
+++ b/ui/aura/desktop.cc
@@ -98,6 +98,7 @@ void Desktop::OnHostResized(const gfx::Size& size) {
   gfx::Rect bounds(0, 0, size.width(), size.height());
   compositor_->WidgetSizeChanged(size);
   window_->SetBounds(bounds);
+  FOR_EACH_OBSERVER(Observer, observers_, OnDesktopResized(size));
 }
 
 void Desktop::ScheduleDraw() {
@@ -164,6 +165,18 @@ MessageLoop::Dispatcher* Desktop::GetDispatcher() {
   return host_.get();
 }
 
+void Desktop::AddObserver(Desktop::Observer* observer) {
+  observers_.AddObserver(observer);
+}
+
+void Desktop::RemoveObserver(Desktop::Observer* observer) {
+  observers_.RemoveObserver(observer);
+}
+
+bool Desktop::HasObserver(Desktop::Observer* observer) {
+  return observers_.HasObserver(observer);
+}
+
 // static
 Desktop* Desktop::GetInstance() {
   if (!instance_) {