Hook up ui::Compositor to Display's BeginFrameSource

cc/surfaces/display_unittest.cc

Index: cc/surfaces/display_unittest.cc
diff --git a/cc/surfaces/display_unittest.cc b/cc/surfaces/display_unittest.cc
index cbc7e34e378d4d6cf74faf92fb87d72fabd91550..fe61e2241106d9eb10cf10ba9fd7b9845b6b9503 100644
--- a/cc/surfaces/display_unittest.cc
+++ b/cc/surfaces/display_unittest.cc
@@ -93,7 +93,6 @@ class DisplayTest : public testing::Test {
   TestSoftwareOutputDevice* software_output_device_;
   scoped_ptr<FakeOutputSurface> output_surface_;
   FakeOutputSurface* output_surface_ptr_;
-  FakeBeginFrameSource fake_begin_frame_source_;
   scoped_refptr<base::NullTaskRunner> task_runner_;
   scoped_ptr<SharedBitmapManager> shared_bitmap_manager_;
 };
@@ -107,6 +106,12 @@ class TestDisplayClient : public DisplayClient {
                              base::TimeDelta interval) override {}
   void OutputSurfaceLost() override {}
   void SetMemoryPolicy(const ManagedMemoryPolicy& policy) override {}
+  BeginFrameSource* BeginFrameSourceForChildren() override {
+    return &fake_begin_frame_source_;
+  }
+
+ private:
+  FakeBeginFrameSource fake_begin_frame_source_;
 };
 
 class TestDisplayScheduler : public DisplayScheduler {
@@ -163,7 +168,7 @@ TEST_F(DisplayTest, DisplayDamaged) {
   Display display(&client, &manager_, shared_bitmap_manager_.get(), nullptr,
                   settings);
 
-  TestDisplayScheduler scheduler(&display, &fake_begin_frame_source_,
+  TestDisplayScheduler scheduler(&display, client.BeginFrameSourceForChildren(),
                                  task_runner_.get());
   display.Initialize(std::move(output_surface_), &scheduler);
 
@@ -429,7 +434,7 @@ TEST_F(DisplayTest, Finish) {
   Display display(&client, &manager_, shared_bitmap_manager_.get(), nullptr,
                   settings);
 
-  TestDisplayScheduler scheduler(&display, &fake_begin_frame_source_,
+  TestDisplayScheduler scheduler(&display, client.BeginFrameSourceForChildren(),
                                  task_runner_.get());
   display.Initialize(std::move(output_surface_), &scheduler);