cc: Create ProxyBeginFrameSource

cc/layers/layer_unittest.cc

Index: cc/layers/layer_unittest.cc
diff --git a/cc/layers/layer_unittest.cc b/cc/layers/layer_unittest.cc
index 460726f55335658ec76239bc5608fe9ea0e9314e..3a6bf00ef46a1033e7690ba6da239963e20dd2e9 100644
--- a/cc/layers/layer_unittest.cc
+++ b/cc/layers/layer_unittest.cc
@@ -44,6 +44,7 @@ class MockLayerTreeHost : public LayerTreeHost {
       : LayerTreeHost(client, nullptr, nullptr, LayerTreeSettings()) {
     InitializeSingleThreaded(client,
                              base::MessageLoopProxy::current(),
+                             nullptr,
                              nullptr);
   }
 
@@ -938,6 +939,7 @@ class LayerTreeHostFactory {
                gpu_memory_buffer_manager_.get(),
                LayerTreeSettings(),
                base::MessageLoopProxy::current(),
+               nullptr,
                nullptr);
   }
 
@@ -949,6 +951,7 @@ class LayerTreeHostFactory {
                gpu_memory_buffer_manager_.get(),
                settings,
                base::MessageLoopProxy::current(),
+               nullptr,
                nullptr);
   }