Do not register synthetic field trial before initializing TaskScheduler.

chrome/browser/chrome_browser_main.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 CHROME_BROWSER_CHROME_BROWSER_MAIN_H_
 #define CHROME_BROWSER_CHROME_BROWSER_MAIN_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 84 matching lines @@
   }
   const base::FilePath& user_data_dir() const {
     return user_data_dir_;
   }
 
   Profile* profile() { return profile_; }
 
   const PrefService* local_state() const { return local_state_; }
 
  private:
-  // Sets up the field trials and related initialization. Call only after
-  // about:flags have been converted to switches.
+  // Sets up field trials. When this returns, FieldTrialList and FeatureList
+  // have been populated with information from the server, the command line,
+  // about:flags and testing configs. Call only after about:flags have been
+  // converted to switches.
   void SetupFieldTrials();
 
   // Constructs the metrics service and initializes metrics recording.
   void SetupMetrics();
 
   // Starts recording of metrics. This can only be called after we have a file
   // thread.
   void StartMetricsRecording();
 
   // Record time from process startup to present time in an UMA histogram.
@@ skipping 78 matching lines @@
 
   // Members initialized in PreMainMessageLoopRun, needed in
   // PreMainMessageLoopRunThreadsCreated.
   PrefService* local_state_;
   base::FilePath user_data_dir_;
 
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserMainParts);
 };
 
 #endif  // CHROME_BROWSER_CHROME_BROWSER_MAIN_H_