Add hooks for flushing input from BeginFrame dispatch on Aura

content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc

Index: content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc
diff --git a/content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc b/content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc
index 77b00e96b01d397ec230147c90212c5b66beb885..ef88289eebcd9b4d5bdaf93a8544c3a63adb8fed 100644
--- a/content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc
+++ b/content/browser/renderer_host/begin_frame_observer_proxy_unittest.cc
@@ -94,4 +94,28 @@ TEST_F(BeginFrameObserverProxyTest, BeginFrameScheduling) {
   Mock::VerifyAndClearExpectations(&client);
 }
 
+TEST_F(BeginFrameObserverProxyTest, SingleBeginFrameScheduling) {
+  MockBeginFrameObserverProxyClient client;
+  BeginFrameObserverProxy begin_frame_observer(&client);
+  begin_frame_observer.SetCompositor(compositor());
+  begin_frame_observer.SetNeedsOneBeginFrame();
+
+  // SendBeginFrame is called when new |args| is delivered.
+  cc::BeginFrameArgs args = cc::CreateBeginFrameArgsForTesting(
+      BEGINFRAME_FROM_HERE, base::TimeTicks::FromInternalValue(33));
+  EXPECT_CALL(client, SendBeginFrame(args));
+  compositor()->SendBeginFramesToChildren(args);
+  Mock::VerifyAndClearExpectations(&client);
+
+  // SendBeginFrame is not called when new |args2| is delivered, as the
+  // single frame request was already satisified.
+  cc::BeginFrameArgs args2 = cc::CreateBeginFrameArgsForTesting(
+      BEGINFRAME_FROM_HERE, base::TimeTicks::FromInternalValue(66));
+  EXPECT_CALL(client, SendBeginFrame(_)).Times(0);
+  compositor()->SendBeginFramesToChildren(args2);
+  Mock::VerifyAndClearExpectations(&client);
+
+  begin_frame_observer.ResetCompositor();
+}
+
 }  // namespace content