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

base/trace_event/trace_event_win.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.
 
 // This file contains the Windows-specific declarations for trace_event.h.
 #ifndef BASE_TRACE_EVENT_TRACE_EVENT_WIN_H_
 #define BASE_TRACE_EVENT_TRACE_EVENT_WIN_H_
 
 #include <string>
 
 #include "base/base_export.h"
 #include "base/trace_event/trace_event.h"
 #include "base/win/event_trace_provider.h"
 
 // Fwd.
 template <typename Type>
 struct StaticMemorySingletonTraits;
 
 namespace base {
-namespace trace_event {
+namespace debug {
 
 // This EtwTraceProvider subclass implements ETW logging
 // for the macros above on Windows.
 class BASE_EXPORT TraceEventETWProvider : public base::win::EtwTraceProvider {
  public:
    static const size_t kUseStrlen = static_cast<size_t>(-1);
 
   // Start logging trace events.
   // This is a noop in this implementation.
   static bool StartTracing();
@@ skipping 81 matching lines @@
   CAPTURE_STACK_TRACE = 0x0001,
 };
 
 // The event format consists of:
 // The "name" string as a zero-terminated ASCII string.
 // The id pointer in the machine bitness.
 // The "extra" string as a zero-terminated ASCII string.
 // Optionally the stack trace, consisting of a DWORD "depth", followed
 //    by an array of void* (machine bitness) of length "depth".
 
-}  // 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::kChromeTraceProviderName;
-using base::trace_event::kTraceEventClass32;
-using base::trace_event::kTraceEventClass64;
-using base::trace_event::kTraceEventTypeBegin;
-using base::trace_event::kTraceEventTypeEnd;
-using base::trace_event::kTraceEventTypeInstant;
-using base::trace_event::TraceEventETWProvider;
 }  // namespace debug
 }  // namespace base
 
 #endif  // BASE_TRACE_EVENT_TRACE_EVENT_WIN_H_