Do not register synthetic field trial before initializing TaskScheduler.

chrome/browser/chrome_browser_main.h

Index: chrome/browser/chrome_browser_main.h
diff --git a/chrome/browser/chrome_browser_main.h b/chrome/browser/chrome_browser_main.h
index 449cf9750528e764886ac93e006c4aaa0d747053..06df076a32de6325411dc10f05b6fa1e114c6872 100644
--- a/chrome/browser/chrome_browser_main.h
+++ b/chrome/browser/chrome_browser_main.h
@@ -102,8 +102,10 @@ class ChromeBrowserMainParts : public content::BrowserMainParts {
   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.