Adding a field trial for testing --force-compositing-mode on 50% of

chrome/browser/chrome_browser_main.h

Index: chrome/browser/chrome_browser_main.h
===================================================================
--- chrome/browser/chrome_browser_main.h	(revision 140632)
+++ chrome/browser/chrome_browser_main.h	(working copy)
@@ -52,6 +52,10 @@
   // Add additional ChromeBrowserMainExtraParts.
   virtual void AddParts(ChromeBrowserMainExtraParts* parts);
 
+  static bool in_force_compositing_mode_trial() {
+    return in_force_compositing_mode_trial_;
+  }

[Ilya Sherman, 2012/06/06 22:31:51]

Do we really need to cache this, rather than querying it from FieldTrialList?  I
suspect that we shouldn't be adding any new methods to the public interface for
ChromeBrowserMainParts...

[vangelis, 2012/06/06 23:44:44]

I removed the public method and replaced it with a global.. This is inline with
what some of the other field trials are actually doing.  Regarding caching, I
only see two options:

1. Cache the group value
2. Expose the name of the trial and the enable group and query every time I need
the value.

Either way we end up with some global data that needs to be exposed across
files.  #1 eliminates unnecessary dictionary searches so it seems better.

I'm open to other suggestions though.

[Ilya Sherman, 2012/06/07 05:27:24]

I'd prefer #2, as it only requires global /constants/, which are a different
animal altogether from global variables.  If you strongly prefer a cached
global, though, I would at least recommend defining it in a separate header -- I
don't think this CL ought to change any publicly exported state in
chrome_browser_main.h.

+
  protected:
   explicit ChromeBrowserMainParts(
       const content::MainFunctionParams& parameters);
@@ -129,6 +133,9 @@
   // Field trial for testing domain bound certs.
   void DomainBoundCertsFieldTrial();
 
+  // Field trial for testing compositing on all pages.
+  void ForceCompositingModeFieldTrial();
+
   // A collection of field trials intended to test the uniformity and
   // correctness of the field trial control, bucketing and reporting systems.
   void SetupUniformityFieldTrials();
@@ -215,6 +222,10 @@
   // network stack, as this can only be done once.
   static bool disable_enforcing_cookie_policies_for_tests_;
 
+  // Set to true if the force-compositing-mode trial has been enabled for
+  // this client.
+  static bool in_force_compositing_mode_trial_;
+
   friend class BrowserMainTest;
   FRIEND_TEST_ALL_PREFIXES(BrowserMainTest,
                            WarmConnectionFieldTrial_WarmestSocket);