Update from https://crrev.com/316786

base/trace_event/trace_event_impl.h

 // Copyright (c) 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.
 
 
 #ifndef BASE_TRACE_EVENT_TRACE_EVENT_IMPL_H_
 #define BASE_TRACE_EVENT_TRACE_EVENT_IMPL_H_
 
 #include <stack>
 #include <string>
@@ skipping 792 matching lines @@
   OutputCallback flush_output_callback_;
   scoped_refptr<MessageLoopProxy> flush_message_loop_proxy_;
   subtle::AtomicWord generation_;
 
   DISALLOW_COPY_AND_ASSIGN(TraceLog);
 };
 
 }  // namespace trace_event
 }  // namespace base
 
-// 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 base {
-namespace debug {
-using base::trace_event::CategoryFilter;
-using base::trace_event::ConvertableToTraceFormat;
-using base::trace_event::RECORD_UNTIL_FULL;
-using base::trace_event::RECORD_CONTINUOUSLY;
-using base::trace_event::RECORD_AS_MUCH_AS_POSSIBLE;
-using base::trace_event::TraceEventHandle;
-using base::trace_event::TraceLog;
-using base::trace_event::TraceLogStatus;
-using base::trace_event::TraceOptions;
-using base::trace_event::TraceResultBuffer;
-}  // namespace debug
-}  // namespace base
-
 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_IMPL_H_