[cc]: Add a BeginMainFrameNotExpectedSoon signal and route it to the RendererScheduler.

cc/trees/thread_proxy.cc

Index: cc/trees/thread_proxy.cc
diff --git a/cc/trees/thread_proxy.cc b/cc/trees/thread_proxy.cc
index db69b8203def40e71e3bf89575907a0be09da1ee..6e41790b92e981a3292f3762470f5f8b1f31c8c1 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -695,6 +695,12 @@ void ThreadProxy::ScheduledActionSendBeginMainFrame() {
   impl().timing_history.DidBeginMainFrame();
 }
 
+void ThreadProxy::SendBeginMainFrameNotExpectedSoon() {
+  Proxy::MainThreadTaskRunner()->PostTask(
+      FROM_HERE, base::Bind(&ThreadProxy::BeginMainFrameNotExpectedSoon,
+                            main_thread_weak_ptr_));
+}
+
 void ThreadProxy::BeginMainFrame(
     scoped_ptr<BeginMainFrameAndCommitState> begin_main_frame_state) {
   benchmark_instrumentation::ScopedBeginFrameTask begin_frame_task(
@@ -855,6 +861,11 @@ void ThreadProxy::BeginMainFrame(
   layer_tree_host()->DidBeginMainFrame();
 }
 
+void ThreadProxy::BeginMainFrameNotExpectedSoon() {
+  TRACE_EVENT0("cc", "ThreadProxy::BeginMainFrameNotExpectedSoon");

[Sami, 2015/02/11 15:28:25]

DCHECK(IsMainThread());

[rmcilroy, 2015/02/13 16:32:45]

Done.

+  layer_tree_host()->BeginMainFrameNotExpectedSoon();
+}
+
 void ThreadProxy::StartCommitOnImplThread(CompletionEvent* completion,
                                           ResourceUpdateQueue* raw_queue) {
   TRACE_EVENT0("cc", "ThreadProxy::StartCommitOnImplThread");