Add more logging to cc scheduler to debug RAF frame loss.

cc/scheduler/scheduler.cc

 // Copyright 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/scheduler/scheduler.h"
 
 #include <algorithm>
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "base/debug/trace_event_argument.h"
@@ skipping 614 matching lines @@
 
   base::AutoReset<bool> mark_inside(&inside_process_scheduled_actions_, true);
 
   SchedulerStateMachine::Action action;
   do {
     action = state_machine_.NextAction();
     TRACE_EVENT1(TRACE_DISABLED_BY_DEFAULT("cc.debug.scheduler"),
                  "SchedulerStateMachine",
                  "state",
                  AsValue());
+    VLOG(2) << "Scheduler::ProcessScheduledActions: "
+            << SchedulerStateMachine::ActionToString(action) << " "
+            << state_machine_.GetStatesForDebugging();
     state_machine_.UpdateState(action);
     base::AutoReset<SchedulerStateMachine::Action>
         mark_inside_action(&inside_action_, action);
     switch (action) {
       case SchedulerStateMachine::ACTION_NONE:
         break;
       case SchedulerStateMachine::ACTION_ANIMATE:
         client_->ScheduledActionAnimate();
         break;
       case SchedulerStateMachine::ACTION_SEND_BEGIN_MAIN_FRAME:
-        VLOG(2) << "Scheduler::ProcessScheduledActions: "
-                   "ACTION_SEND_BEGIN_MAIN_FRAME";
         client_->ScheduledActionSendBeginMainFrame();
         break;
       case SchedulerStateMachine::ACTION_COMMIT:
         client_->ScheduledActionCommit();
         break;
       case SchedulerStateMachine::ACTION_UPDATE_VISIBLE_TILES:
         client_->ScheduledActionUpdateVisibleTiles();
         break;
       case SchedulerStateMachine::ACTION_ACTIVATE_SYNC_TREE:
         client_->ScheduledActionActivateSyncTree();
@@ skipping 100 matching lines @@
 }
 
 bool Scheduler::IsBeginMainFrameSentOrStarted() const {
   return (state_machine_.commit_state() ==
               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_SENT ||
           state_machine_.commit_state() ==
               SchedulerStateMachine::COMMIT_STATE_BEGIN_MAIN_FRAME_STARTED);
 }
 
 }  // namespace cc