Add queued_time_ms trace for events in message loop

base/location.h

Index: base/location.h
diff --git a/base/location.h b/base/location.h
index 05a4f66109058242f80a9036248ae57cef725261..3a95415c33495d7533094d3484896a1929739b46 100644
--- a/base/location.h
+++ b/base/location.h
@@ -9,6 +9,13 @@
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace base {
+namespace debug {
+class ConvertableToTraceFormat;
+}
+}
 
 namespace tracked_objects {
 
@@ -47,6 +54,7 @@ class BASE_EXPORT Location {
   const void* program_counter() const { return program_counter_; }
 
   std::string ToString() const;
+  scoped_ptr<base::debug::ConvertableToTraceFormat> ToTraceFormat() const;
 
   // Translate the some of the state in this instance into a human readable
   // string with HTML characters in the function names escaped, and append that