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

cc/output/filter_operation.h

 // Copyright 2013 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_OUTPUT_FILTER_OPERATION_H_
 #define CC_OUTPUT_FILTER_OPERATION_H_
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "cc/base/cc_export.h"
 #include "skia/ext/refptr.h"
 #include "third_party/skia/include/core/SkColor.h"
 #include "third_party/skia/include/core/SkImageFilter.h"
 #include "third_party/skia/include/core/SkRegion.h"
 #include "third_party/skia/include/core/SkScalar.h"
 #include "ui/gfx/geometry/point.h"
 
 namespace base {
-namespace trace_event {
+namespace debug {
 class TracedValue;
 }
-
-// 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::TracedValue;
+class Value;
 }
-class Value;
-}  // namespace base
 
 namespace cc {
 
 class CC_EXPORT FilterOperation {
  public:
   enum FilterType {
     GRAYSCALE,
     SEPIA,
     SATURATE,
     HUE_ROTATE,
@@ skipping 218 matching lines @@
   SkColor drop_shadow_color_;
   skia::RefPtr<SkImageFilter> image_filter_;
   SkScalar matrix_[20];
   int zoom_inset_;
   SkRegion region_;
 };
 
 }  // namespace cc
 
 #endif  // CC_OUTPUT_FILTER_OPERATION_H_