Cleaning up compositing field trial code and enable FCM in beta/stable

chrome/browser/gpu_util.h

Index: chrome/browser/gpu_util.h
diff --git a/chrome/browser/gpu_util.h b/chrome/browser/gpu_util.h
index 36b5459338cd3c2450ccf7792bcdc32909f208f5..10efc25586182163820d8b83e5bb54ebbdf330ec 100644
--- a/chrome/browser/gpu_util.h
+++ b/chrome/browser/gpu_util.h
@@ -69,12 +69,8 @@ base::DictionaryValue* GpuInfoAsDictionaryValue();
 // Send UMA histograms about the enabled features.
 void UpdateStats();
 
-// Returns whether this client has been selected for the force-compositing-mode
-// or threaded-compositor trial.
-bool InForceCompositingModeOrThreadTrial();
-
-// Sets up the force-compositing-mode field trial.
-void InitializeForceCompositingModeFieldTrial();
+// Sets up force-compositing-mode and threaded compositing field trials.
+void InitializeCompositingFieldTrial();
 
 }  // namespace gpu_util