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

content/renderer/scheduler/task_queue_manager.h

Index: content/renderer/scheduler/task_queue_manager.h
diff --git a/content/renderer/scheduler/task_queue_manager.h b/content/renderer/scheduler/task_queue_manager.h
index 100c6d570ca173b44587af4712cbeadcac30d860..02b226c54672b9fe0daf9081e6a28528ac3db9b6 100644
--- a/content/renderer/scheduler/task_queue_manager.h
+++ b/content/renderer/scheduler/task_queue_manager.h
@@ -16,11 +16,18 @@
 #include "content/common/content_export.h"
 
 namespace base {
-namespace debug {
+namespace trace_event {
 class ConvertableToTraceFormat;
 class TracedValue;
 }
+
+// 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 debug {
+using ::base::trace_event::ConvertableToTraceFormat;
+using ::base::trace_event::TracedValue;
 }
+}  // namespace base
 
 namespace content {
 namespace internal {