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

base/trace_event/trace_event_win_unittest.cc

Index: base/trace_event/trace_event_win_unittest.cc
diff --git a/base/trace_event/trace_event_win_unittest.cc b/base/trace_event/trace_event_win_unittest.cc
index a411301ecb377f5e98e913d3fb23008ca499aa5b..7f1004ea9b3f2cecae0206ad604b1260e1660d02 100644
--- a/base/trace_event/trace_event_win_unittest.cc
+++ b/base/trace_event/trace_event_win_unittest.cc
@@ -20,7 +20,7 @@
 #include <initguid.h>  // NOLINT - must be last include.
 
 namespace base {
-namespace debug {
+namespace trace_event {
 
 namespace {
 
@@ -315,5 +315,5 @@ TEST_F(TraceEventWinTest, Macros) {
   PlayLog();
 }
 
-}  // namespace debug
+}  // namespace trace_event
 }  // namespace base