Update from https://crrev.com/303153

base/tracked_objects.h

 // Copyright (c) 2012 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_TRACKED_OBJECTS_H_
 #define BASE_TRACKED_OBJECTS_H_
 
 #include <map>
 #include <set>
 #include <stack>
@@ skipping 448 matching lines @@
   // on.  This is currently a compiled option, atop TrackingStatus().
   static bool TrackingParentChildStatus();
 
   // Marks a start of a tracked run. It's super fast when tracking is disabled,
   // and has some internal side effects when we are tracking, so that we can
   // deduce the amount of time accumulated outside of execution of tracked runs.
   // The task that will be tracked is passed in as |parent| so that parent-child
   // relationships can be (optionally) calculated.
   static void PrepareForStartOfRun(const Births* parent);
 
+  // Enables profiler timing.
+  static void EnableProfilerTiming();
+
   // Provide a time function that does nothing (runs fast) when we don't have
   // the profiler enabled.  It will generally be optimized away when it is
   // ifdef'ed to be small enough (allowing the profiler to be "compiled out" of
   // the code).
   static TrackedTime Now();
 
   // Use the function |now| to provide current times, instead of calling the
   // TrackedTime::Now() function.  Since this alternate function is being used,
   // the other time arguments (used for calculating queueing delay) will be
   // ignored.
@@ skipping 302 matching lines @@
   ~ProcessDataSnapshot();
 
   std::vector<TaskSnapshot> tasks;
   std::vector<ParentChildPairSnapshot> descendants;
   int process_id;
 };
 
 }  // namespace tracked_objects
 
 #endif  // BASE_TRACKED_OBJECTS_H_