Add test for begin frames when using SingleThreadProxy.

cc/trees/layer_tree_host_unittest.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/layer_tree_host.h"
 
 #include <algorithm>
 
 #include "base/auto_reset.h"
 #include "base/location.h"
@@ skipping 2758 matching lines @@
   void CallOnDraw() {
     // Synchronous compositor does not draw unless told to do so by the output
     // surface.
     output_surface()->client()->OnDraw();
   }
 };
 
 MULTI_THREAD_TEST_F(
     LayerTreeHostTestAbortedCommitDoesntStallSynchronousCompositor);
 
+class LayerTreeHostTestBeginFrameNotificationSynchronousCompositor
+    : public LayerTreeHostTest {
+ protected:
+  void BeginTest() override {
+    saw_will_begin_impl_frame_ = false;
+    PostCompositeImmediatelyToMainThread();
+  }
+
+  void InitializeSettings(LayerTreeSettings* settings) override {
+    settings->using_synchronous_renderer_compositor = true;
+    settings->single_thread_proxy_scheduler = false;
+  }
+
+  void WillBeginImplFrameOnThread(LayerTreeHostImpl* impl,
+                                  const BeginFrameArgs& args) override {
+    EXPECT_EQ(base::TimeTicks(), args.deadline);
+    EXPECT_EQ(BeginFrameArgs::DefaultInterval(), args.interval);
+    saw_will_begin_impl_frame_ = true;

[enne (OOO), 2015/05/04 22:30:27]

I guess it was my understanding that it was also that BeginMainFrame happens
between this and DidBeginImplFrameDeadline?

+  }
+
+  void DidCommitAndDrawFrame() override { EndTest(); }
+
+  void AfterTest() override { EXPECT_TRUE(saw_will_begin_impl_frame_); }
+
+ private:
+  bool saw_will_begin_impl_frame_;
+};
+
+TEST_F(LayerTreeHostTestBeginFrameNotificationSynchronousCompositor,
+       BeginFrameReceived) {
+  RunTest(false, true, true);
+}
+
 class LayerTreeHostTestAbortedCommitDoesntStallDisabledVsync
     : public LayerTreeHostTestAbortedCommitDoesntStall {
   void InitializeSettings(LayerTreeSettings* settings) override {
     LayerTreeHostTestAbortedCommitDoesntStall::InitializeSettings(settings);
     settings->throttle_frame_production = false;
   }
 };
 
 MULTI_THREAD_TEST_F(LayerTreeHostTestAbortedCommitDoesntStallDisabledVsync);
 
@@ skipping 4203 matching lines @@
   void AfterTest() override {}
 
   scoped_refptr<FakePictureLayer> content_child_layer_;
   FakeContentLayerClient client_;
 };
 
 SINGLE_AND_MULTI_THREAD_TEST_F(
     LayerTreeTestReflectionMaskLayerForSurfaceWithUnclippedChild);
 
 }  // namespace cc