cc: Make separate interface for BeginFrame ipc from OutputSurface

cc/trees/layer_tree_host_unittest.cc

Index: cc/trees/layer_tree_host_unittest.cc
diff --git a/cc/trees/layer_tree_host_unittest.cc b/cc/trees/layer_tree_host_unittest.cc
index c5dbe0d79a624d9e346e5ca84cc1a325c892f27f..a48c8fad2d1d048e009b072a763305a3ca006add 100644
--- a/cc/trees/layer_tree_host_unittest.cc
+++ b/cc/trees/layer_tree_host_unittest.cc
@@ -1980,7 +1980,8 @@ TEST(LayerTreeHostTest, PartialUpdatesWithGLRenderer) {
                                           shared_bitmap_manager.get(),
                                           NULL,
                                           settings,
-                                          base::MessageLoopProxy::current());
+                                          base::MessageLoopProxy::current(),
+                                          nullptr);

[brianderson, 2014/10/18 00:08:45]

Why is an external source used in the LayerTree tests, but not here?

[simonhong, 2014/10/23 01:03:08]

These four tests didn't use external BeginFrameSource.
But, all other tests except them overrides begin_frame_scheduling_enabled value
when they needed.

   client.SetLayerTreeHost(host.get());
   host->Composite(base::TimeTicks::Now());
 
@@ -2002,7 +2003,8 @@ TEST(LayerTreeHostTest, PartialUpdatesWithSoftwareRenderer) {
                                           shared_bitmap_manager.get(),
                                           NULL,
                                           settings,
-                                          base::MessageLoopProxy::current());
+                                          base::MessageLoopProxy::current(),
+                                          nullptr);
   client.SetLayerTreeHost(host.get());
   host->Composite(base::TimeTicks::Now());
 
@@ -2024,7 +2026,8 @@ TEST(LayerTreeHostTest, PartialUpdatesWithDelegatingRendererAndGLContent) {
                                           shared_bitmap_manager.get(),
                                           NULL,
                                           settings,
-                                          base::MessageLoopProxy::current());
+                                          base::MessageLoopProxy::current(),
+                                          nullptr);
   client.SetLayerTreeHost(host.get());
   host->Composite(base::TimeTicks::Now());
 
@@ -2047,7 +2050,8 @@ TEST(LayerTreeHostTest,
                                           shared_bitmap_manager.get(),
                                           NULL,
                                           settings,
-                                          base::MessageLoopProxy::current());
+                                          base::MessageLoopProxy::current(),
+                                          nullptr);
   client.SetLayerTreeHost(host.get());
   host->Composite(base::TimeTicks::Now());