Add a |scope| argument to TRACE_EVENT_INSTANT* and require its presence.

cc/animation/animation.cc

 // Copyright 2012 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/animation/animation.h"
 
 #include <cmath>
 
 #include "base/debug/trace_event.h"
 #include "base/string_util.h"
@@ skipping 106 matching lines @@
 
   char state_buffer[256];
   base::snprintf(state_buffer,
                  sizeof(state_buffer),
                  "%s->%s",
                  old_run_state_name,
                  new_run_state_name);
 
   TRACE_EVENT_INSTANT2("cc",
                        "LayerAnimationController::SetRunState",
+                       TRACE_EVENT_SCOPE_THREAD,
                        "Name",
                        TRACE_STR_COPY(name_buffer),
                        "State",
                        TRACE_STR_COPY(state_buffer));
 }
 
 void Animation::Suspend(double monotonic_time) {
   SetRunState(Paused, monotonic_time);
   suspended_ = true;
 }
@@ skipping 90 matching lines @@
   // the main thread.
   if (run_state_ == Animation::Paused ||
       other->run_state_ == Animation::Paused) {
     other->run_state_ = run_state_;
     other->pause_time_ = pause_time_;
     other->total_paused_time_ = total_paused_time_;
   }
 }
 
 }  // namespace cc