Provide a vsync notification to the renderer

cc/layer_tree_host_unittest.cc

Index: cc/layer_tree_host_unittest.cc
diff --git a/cc/layer_tree_host_unittest.cc b/cc/layer_tree_host_unittest.cc
index 63799bf0579bce80023eab9f5d3674762b14a277..4e2f7377ab291c81376cb99c6575b569346df79e 100644
--- a/cc/layer_tree_host_unittest.cc
+++ b/cc/layer_tree_host_unittest.cc
@@ -2104,5 +2104,58 @@ TEST_F(LayerTreeHostTestMaxPendingFrames, GLRenderer)
     runTest(true);
 }
 
+// Verify that the vsync notification is used to initiate rendering.
+class LayerTreeHostTestVSyncNotification : public LayerTreeHostTest {
+public:
+    LayerTreeHostTestVSyncNotification()
+    {
+        m_settings.renderVSyncNotificationEnabled = true;
+    }
+
+    virtual void beginTest() OVERRIDE
+    {
+        postSetNeedsCommitToMainThread();
+    }
+
+    virtual void commitCompleteOnThread(LayerTreeHostImpl* impl) OVERRIDE
+    {
+        FakeOutputSurface* fakeOutputSurface =
+            reinterpret_cast<FakeOutputSurface*>(impl->outputSurface());
+
+        // The vsync notification is turned off now but will get enabled once we
+        // return, so post a task to trigger it.
+        ASSERT_FALSE(fakeOutputSurface->vsync_notification_enabled());
+        postVSyncOnImplThread(fakeOutputSurface);
+    }
+
+    void postVSyncOnImplThread(FakeOutputSurface* fakeOutputSurface)
+    {
+        DCHECK(implThread());
+        implThread()->postTask(base::Bind(&LayerTreeHostTestVSyncNotification::DidVSync,
+                               base::Unretained(this), base::Unretained(fakeOutputSurface)));
+    }
+
+    void DidVSync(FakeOutputSurface* fakeOutputSurface)
+    {
+        ASSERT_TRUE(fakeOutputSurface->vsync_notification_enabled());
+        fakeOutputSurface->DidVSync(m_frameTime);
+    }
+
+    virtual bool prepareToDrawOnThread(LayerTreeHostImpl*, LayerTreeHostImpl::FrameData&, bool result) OVERRIDE
+    {
+        endTest();
+        return true;
+    }
+
+    virtual void afterTest() OVERRIDE
+    {
+    }
+
+private:
+    base::TimeTicks m_frameTime;
+};
+
+MULTI_THREAD_TEST_F(LayerTreeHostTestVSyncNotification);
+
 }  // namespace
 }  // namespace cc