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

content/child/child_thread.h

Index: content/child/child_thread.h
diff --git a/content/child/child_thread.h b/content/child/child_thread.h
index 24cfc61f22cbbaf37a51e700b1764c09dee9240b..1b3dd37f65f6625331949182a76f285240029359 100644
--- a/content/child/child_thread.h
+++ b/content/child/child_thread.h
@@ -21,8 +21,11 @@
 namespace base {
 class MessageLoop;
 
-namespace debug {
+namespace trace_event {
 class TraceMemoryController;
+}  // namespace trace_event
+namespace debug {

[Primiano Tucci (use gerrit), 2015/01/27 14:34:11]

ditto (remove trailing comment)

+using ::base::trace_event::TraceMemoryController;
 }  // namespace debug

[Primiano Tucci (use gerrit), 2015/01/27 14:34:11]

nit: blankline

 }  // namespace base