cc: Make separate interface for BeginFrame ipc from OutputSurface

cc/trees/layer_tree_host_unittest_scroll.cc

Index: cc/trees/layer_tree_host_unittest_scroll.cc
diff --git a/cc/trees/layer_tree_host_unittest_scroll.cc b/cc/trees/layer_tree_host_unittest_scroll.cc
index 82f3d55f41b716c456cfcc9ec48235cc11892708..d2af3a9f674a4b7331a498ca78ed622feb93848b 100644
--- a/cc/trees/layer_tree_host_unittest_scroll.cc
+++ b/cc/trees/layer_tree_host_unittest_scroll.cc
@@ -8,6 +8,7 @@
 #include "cc/layers/layer.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/picture_layer.h"
+#include "cc/scheduler/begin_frame_source.h"
 #include "cc/test/fake_content_layer_client.h"
 #include "cc/test/fake_layer_tree_host_client.h"
 #include "cc/test/fake_picture_layer.h"
@@ -1136,7 +1137,8 @@ TEST(LayerTreeHostFlingTest, DidStopFlingingThread) {
                                     NULL,
                                     settings,
                                     base::MessageLoopProxy::current(),
-                                    impl_thread.message_loop_proxy());
+                                    impl_thread.message_loop_proxy(),
+                                    nullptr);
 
   impl_thread.message_loop_proxy()
       ->PostTask(FROM_HERE,