[UMA] Use proper C++ objects to serialize tracked_objects across process boundaries.

base/profiler/tracked_time.h

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef BASE_PROFILER_TRACKED_TIME_H_
 #define BASE_PROFILER_TRACKED_TIME_H_
 
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/time.h"
 
 namespace tracked_objects {
 
+// TODO(isherman): Shouldn't this be explicitly an int32 or something like that?
 typedef int DurationInt;
 
 //------------------------------------------------------------------------------
 
 #define USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS
 
 #if defined(USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS)
 
 // TimeTicks maintains a wasteful 64 bits of data (we need less than 32), and on
 // windows, a 64 bit timer is expensive to even obtain. We use a simple
@@ skipping 54 matching lines @@
 // with a more thoroughly tested class.
 
 typedef base::TimeTicks TrackedTime;
 typedef base::TimeDelta Duration;
 
 #endif  // USE_FAST_TIME_CLASS_FOR_DURATION_CALCULATIONS
 
 }  // namespace tracked_objects
 
 #endif  // BASE_PROFILER_TRACKED_TIME_H_