Tighter sync and faster ACK on SwapBuffers/PostSubBuffers

ui/compositor/layer_unittest.cc

Index: ui/compositor/layer_unittest.cc
diff --git a/ui/compositor/layer_unittest.cc b/ui/compositor/layer_unittest.cc
index b46d0a1f06add7ee2b06a56d525ae8a9aef47a8e..ad66befa5348bd2e58214856a7a4b6ef7318478b 100644
--- a/ui/compositor/layer_unittest.cc
+++ b/ui/compositor/layer_unittest.cc
@@ -309,12 +309,14 @@ class NullLayerDelegate : public LayerDelegate {
 // Remembers if it has been notified.
 class TestCompositorObserver : public CompositorObserver {
  public:
-  TestCompositorObserver() : started_(false), ended_(false) {}
+  TestCompositorObserver() : started_(false), will_end_(false), ended_(false) {
+  }
 
-  bool notified() const { return started_ && ended_; }
+  bool notified() const { return started_ && will_end_ && ended_; }
 
   void Reset() {
     started_ = false;
+    will_end_ = false;
     ended_ = false;
   }
 
@@ -323,11 +325,16 @@ class TestCompositorObserver : public CompositorObserver {
     started_ = true;
   }
 
+  virtual void OnCompositingWillEnd(Compositor* compositor) OVERRIDE {
+    will_end_ = true;
+  }
+
   virtual void OnCompositingEnded(Compositor* compositor) OVERRIDE {
     ended_ = true;
   }
 
   bool started_;
+  bool will_end_;
   bool ended_;
 
   DISALLOW_COPY_AND_ASSIGN(TestCompositorObserver);