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

content/renderer/scheduler/renderer_scheduler_impl.cc

Index: content/renderer/scheduler/renderer_scheduler_impl.cc
diff --git a/content/renderer/scheduler/renderer_scheduler_impl.cc b/content/renderer/scheduler/renderer_scheduler_impl.cc
index fbd8cbe605c07dfd3b1a47f62f29c45e33b85fee..ef5b54a79b560a98ca46240d2c7f2898abeebb0e 100644
--- a/content/renderer/scheduler/renderer_scheduler_impl.cc
+++ b/content/renderer/scheduler/renderer_scheduler_impl.cc
@@ -119,6 +119,12 @@ void RendererSchedulerImpl::DidCommitFrameToCompositor() {
   }
 }
 
+void RendererSchedulerImpl::BeginFrameNoLongerRequired() {
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),
+               "RendererSchedulerImpl::BeginFrameNoLongerRequired");
+  // TODO(rmcilroy): Implement long idle times.
+}
+
 void RendererSchedulerImpl::DidReceiveInputEventOnCompositorThread(
     blink::WebInputEvent::Type type) {
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("renderer.scheduler"),