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

cc/scheduler/scheduler_state_machine.h

Index: cc/scheduler/scheduler_state_machine.h
diff --git a/cc/scheduler/scheduler_state_machine.h b/cc/scheduler/scheduler_state_machine.h
index 9dc7817d473c9ad6ee1c719746ca0dd2293238cd..0b063cc6d6e87f94b67dbc58f456e56a79acb281 100644
--- a/cc/scheduler/scheduler_state_machine.h
+++ b/cc/scheduler/scheduler_state_machine.h
@@ -17,12 +17,16 @@
 #include "cc/scheduler/scheduler_settings.h"
 
 namespace base {
-namespace debug {
+namespace trace_event {
 class ConvertableToTraceFormat;
 class TracedValue;
 }
-class Value;
+namespace debug {
+using ::base::trace_event::TracedValue;

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

Nit: blankline

+using ::base::trace_event::ConvertableToTraceFormat;
 }
+class Value;
+}  // namespace base
 
 namespace cc {