Reland of Move tracing namespace from base::debug to base::trace_event.

cc/scheduler/scheduler.h

 // 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.
 
 #ifndef CC_SCHEDULER_SCHEDULER_H_
 #define CC_SCHEDULER_SCHEDULER_H_
 
 #include <deque>
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/power_monitor/power_monitor.h"
 #include "base/power_monitor/power_observer.h"
 #include "base/time/time.h"
 #include "cc/base/cc_export.h"
 #include "cc/output/begin_frame_args.h"
 #include "cc/output/vsync_parameter_observer.h"
 #include "cc/scheduler/begin_frame_source.h"
 #include "cc/scheduler/delay_based_time_source.h"
 #include "cc/scheduler/draw_result.h"
 #include "cc/scheduler/scheduler_settings.h"
 #include "cc/scheduler/scheduler_state_machine.h"
 
 namespace base {
-namespace debug {
+namespace trace_event {
 class ConvertableToTraceFormat;
 }
+
+// TODO(ssid): remove these aliases after the tracing clients are moved to the
+// new trace_event namespace. See crbug.com/451032. ETA: March 2015
+namespace debug {
+using ::base::trace_event::ConvertableToTraceFormat;
+}
 class SingleThreadTaskRunner;
-}
+}  // namespace base
 
 namespace cc {
 
 class SchedulerClient {
  public:
   virtual void WillBeginImplFrame(const BeginFrameArgs& args) = 0;
   virtual void ScheduledActionSendBeginMainFrame() = 0;
   virtual DrawResult ScheduledActionDrawAndSwapIfPossible() = 0;
   virtual DrawResult ScheduledActionDrawAndSwapForced() = 0;
   virtual void ScheduledActionAnimate() = 0;
@@ skipping 216 matching lines @@
 
   friend class SchedulerFrameSourcesConstructor;
   friend class TestSchedulerFrameSourcesConstructor;
 
   DISALLOW_COPY_AND_ASSIGN(Scheduler);
 };
 
 }  // namespace cc
 
 #endif  // CC_SCHEDULER_SCHEDULER_H_