cc: Add logging to help pinpoint lost SetNeedsCommit

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 d015d283f6bd94d431d6e50dc61f2fe800162e78..443c1138830e2a34438cda1af2d79a623f6e2f94 100644
--- a/cc/trees/thread_proxy.cc
+++ b/cc/trees/thread_proxy.cc
@@ -259,6 +259,7 @@ void ThreadProxy::SendCommitRequestToImplThreadIfNeeded() {
   DCHECK(IsMainThread());
   if (main().commit_request_sent_to_impl_thread)
     return;
+  VLOG(2) << "ThreadProxy::SendCommitRequestToImplThreadIfNeeded";

[Ken Russell (switch to Gerrit), 2014/09/10 00:43:41]

Would it be better to log earlier and include the value of
main().commit_request_sent_to_impl_thread?

   main().commit_request_sent_to_impl_thread = true;
   Proxy::ImplThreadTaskRunner()->PostTask(
       FROM_HERE,
@@ -278,6 +279,7 @@ void ThreadProxy::SetNeedsAnimate() {
     return;
 
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsAnimate");
+  VLOG(2) << "ThreadProxy::SetNeedsAnimate";

[Ken Russell (switch to Gerrit), 2014/09/10 00:43:41]

Same question about logging earlier here.

   main().animate_requested = true;
   SendCommitRequestToImplThreadIfNeeded();
 }
@@ -380,6 +382,7 @@ void ThreadProxy::NotifyReadyToActivate() {
 
 void ThreadProxy::SetNeedsCommitOnImplThread() {
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsCommitOnImplThread");
+  VLOG(2) << "ThreadProxy::SetNeedsCommitOnImplThread";
   DCHECK(IsImplThread());
   impl().scheduler->SetNeedsCommit();
 }
@@ -772,6 +775,7 @@ void ThreadProxy::BeginMainFrame(
   // callbacks will trigger another frame.
   main().commit_requested = true;
   main().commit_request_sent_to_impl_thread = true;
+  VLOG(2) << "ThreadProxy::BeginMainFrame: Commit requests silenced.";
 
   layer_tree_host()->ApplyScrollAndScale(
       begin_main_frame_state->scroll_info.get());
@@ -826,8 +830,11 @@ void ThreadProxy::BeginMainFrame(
   // thread.
   if (main().animate_requested) {
     // Forces SetNeedsAnimate to consider posting a commit task.
+    VLOG(2) << "ThreadProxy::BeginMainFrame: RAF requested.";
     main().animate_requested = false;
     SetNeedsAnimate();
+  } else {
+    VLOG(2) << "ThreadProxy::BeginMainFrame: RAF NOT requested.";
   }
 
   if (!updated && can_cancel_this_commit) {