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

base/trace_event/trace_event_impl.h

Index: base/trace_event/trace_event_impl.h
diff --git a/base/trace_event/trace_event_impl.h b/base/trace_event/trace_event_impl.h
index 6d04c76b079fc4da28630dcaa76e30c668a695f5..742f6b6fe61d73aaccd80873104adfb7dd4c57ca 100644
--- a/base/trace_event/trace_event_impl.h
+++ b/base/trace_event/trace_event_impl.h
@@ -27,17 +27,17 @@
 // Older style trace macros with explicit id and extra data
 // Only these macros result in publishing data to ETW as currently implemented.
 #define TRACE_EVENT_BEGIN_ETW(name, id, extra) \
-    base::debug::TraceLog::AddTraceEventEtw( \
+    base::trace_event::TraceLog::AddTraceEventEtw( \
         TRACE_EVENT_PHASE_BEGIN, \
         name, reinterpret_cast<const void*>(id), extra)
 
 #define TRACE_EVENT_END_ETW(name, id, extra) \
-    base::debug::TraceLog::AddTraceEventEtw( \
+    base::trace_event::TraceLog::AddTraceEventEtw( \
         TRACE_EVENT_PHASE_END, \
         name, reinterpret_cast<const void*>(id), extra)
 
 #define TRACE_EVENT_INSTANT_ETW(name, id, extra) \
-    base::debug::TraceLog::AddTraceEventEtw( \
+    base::trace_event::TraceLog::AddTraceEventEtw( \
         TRACE_EVENT_PHASE_INSTANT, \
         name, reinterpret_cast<const void*>(id), extra)
 
@@ -49,7 +49,7 @@ namespace base {
 class WaitableEvent;
 class MessageLoop;
 
-namespace debug {
+namespace trace_event {
 
 // For any argument of type TRACE_VALUE_TYPE_CONVERTABLE the provided
 // class must implement this interface.
@@ -807,6 +807,23 @@ class BASE_EXPORT TraceLog {
   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