Add instrumentation to the MessagePumpMac family of classes.

base/message_loop/message_pump_mac.h

Index: base/message_loop/message_pump_mac.h
diff --git a/base/message_loop/message_pump_mac.h b/base/message_loop/message_pump_mac.h
index 748b26591f0403baaaa88fc9ad070135c8565f3b..61ac7038003470c874684ff41cbf8f43ff6186c6 100644
--- a/base/message_loop/message_pump_mac.h
+++ b/base/message_loop/message_pump_mac.h
@@ -36,6 +36,8 @@
 
 #include <CoreFoundation/CoreFoundation.h>
 
+#include "base/memory/weak_ptr.h"
+
 #if !defined(__OBJC__)
 class NSAutoreleasePool;
 #else  // !defined(__OBJC__)
@@ -57,6 +59,7 @@ class NSAutoreleasePool;
 
 namespace base {
 
+class MessagePumpInstrumentation;
 class RunLoop;
 class TimeTicks;
 
@@ -93,6 +96,11 @@ class MessagePumpCFRunLoopBase : public MessagePump {
   // objects autoreleased by work to fall into the current autorelease pool.
   virtual NSAutoreleasePool* CreateAutoreleasePool();
 
+  // Enables instrumentation of the MessagePump. See MessagePumpInstrumentation
+  // in the implementation for details.
+  void EnableInstrumentation();
+  WeakPtr<MessagePumpInstrumentation> instrumentation_;
+
  private:
   // Timer callback scheduled by ScheduleDelayedWork.  This does not do any
   // work, but it signals work_source_ so that delayed work can be performed