cc: Make separate interface for BeginFrame ipc from OutputSurface

cc/test/scheduler_test_common.h

Index: cc/test/scheduler_test_common.h
diff --git a/cc/test/scheduler_test_common.h b/cc/test/scheduler_test_common.h
index a91fd01b9b4c37c7bee795138677374027ac0287..936b3d1578f2ec3319c5837619b930fd09e372da 100644
--- a/cc/test/scheduler_test_common.h
+++ b/cc/test/scheduler_test_common.h
@@ -163,16 +163,19 @@ class TestScheduler : public Scheduler {
       const SchedulerSettings& scheduler_settings,
       int layer_tree_host_id,
       const scoped_refptr<OrderedSimpleTaskRunner>& task_runner,
-      base::PowerMonitor* power_monitor) {
+      base::PowerMonitor* power_monitor,
+      scoped_ptr<BeginFrameSource> external_begin_frame_source) {
     TestSchedulerFrameSourcesConstructor frame_sources_constructor(
         task_runner.get(), now_src.get());
-    return make_scoped_ptr(new TestScheduler(now_src,
-                                             client,
-                                             scheduler_settings,
-                                             layer_tree_host_id,
-                                             task_runner,
-                                             power_monitor,
-                                             &frame_sources_constructor));
+    return make_scoped_ptr(new TestScheduler(
+                                   now_src,
+                                   client,
+                                   scheduler_settings,
+                                   layer_tree_host_id,
+                                   task_runner,
+                                   power_monitor,
+                                   &frame_sources_constructor,
+                                   external_begin_frame_source.Pass()));
   }
 
   // Extra test helper functionality
@@ -180,6 +183,10 @@ class TestScheduler : public Scheduler {
     return begin_retro_frame_args_.empty();
   }
 
+  bool NeedsBeginFrames() const {
+    return primary_frame_source_->NeedsBeginFrames();
+  }
+
   BeginFrameSource& frame_source() { return *frame_source_; }
 
   virtual ~TestScheduler();
@@ -196,7 +203,8 @@ class TestScheduler : public Scheduler {
       int layer_tree_host_id,
       const scoped_refptr<OrderedSimpleTaskRunner>& test_task_runner,
       base::PowerMonitor* power_monitor,
-      TestSchedulerFrameSourcesConstructor* frame_sources_constructor);
+      TestSchedulerFrameSourcesConstructor* frame_sources_constructor,
+      scoped_ptr<BeginFrameSource> external_begin_frame_source);
 
   scoped_refptr<TestNowSource> now_src_;
 };