Update from chromium https://crrev.com/301725/

base/tracked_objects.h

Index: base/tracked_objects.h
diff --git a/base/tracked_objects.h b/base/tracked_objects.h
index 055cf190d5ede89a25a85e5997a9d3e256f17d38..222f5818b0b73acaa1f828d8688d621d4f2c0337 100644
--- a/base/tracked_objects.h
+++ b/base/tracked_objects.h
@@ -709,6 +709,9 @@ class BASE_EXPORT TaskStopwatch {
   TaskStopwatch();
   ~TaskStopwatch();
 
+  // Starts stopwatch.
+  void Start();
+
   // Stops stopwatch.
   void Stop();
 
@@ -744,12 +747,9 @@ class BASE_EXPORT TaskStopwatch {
   TaskStopwatch* parent_;
 
 #if DCHECK_IS_ON
-  // State of the stopwatch. Stopwatch is first constructed in a running state,
-  // then stopped, then destructed.
-  enum {
-    RUNNING,
-    STOPPED
-  } state_;
+  // State of the stopwatch. Stopwatch is first constructed in a created state
+  // state, then is optionally started/stopped, then destructed.
+  enum { CREATED, RUNNING, STOPPED } state_;
 
   // Currently running stopwatch that is directly nested in this one, if such
   // stopwatch exists. NULL otherwise.