Updated OSX to blacklist multisampling when multiple monitors are connected

content/browser/gpu/gpu_data_manager_impl.h

Index: content/browser/gpu/gpu_data_manager_impl.h
diff --git a/content/browser/gpu/gpu_data_manager_impl.h b/content/browser/gpu/gpu_data_manager_impl.h
index 5fa8780061d4937926d0d27e18317730c7241a0b..d625b7289a4bd23a6d1a000432645e7b7c0a9ebf 100644
--- a/content/browser/gpu/gpu_data_manager_impl.h
+++ b/content/browser/gpu/gpu_data_manager_impl.h
@@ -172,6 +172,9 @@ class CONTENT_EXPORT GpuDataManagerImpl
   void AddGpuSwitchCallback(const GpuSwitchCallback& callback);
   void RemoveGpuSwitchCallback(const GpuSwitchCallback& callback);
 
+  void SetDisplayCount(unsigned int display_count);
+  unsigned int GetDisplayCount() const;
+
  private:
   struct DomainBlockEntry {
     DomainGuilt last_guilt;
@@ -291,6 +294,11 @@ class CONTENT_EXPORT GpuDataManagerImpl
 
   std::vector<GpuSwitchCallback> gpu_switch_callbacks_;
 
+#if defined(OS_MACOSX)
+  // Number of displays, to be used in GPU feature detection.
+  unsigned int display_count_;

[Ken Russell (switch to Gerrit), 2013/05/08 23:53:24]

This won't compile on non-Mac platforms. Given the number of #ifdefs that would
be required to make it compile I think it would be easier to just comment that
it's currently used only on OS X, and define it on all platforms.

+#endif
+
   DISALLOW_COPY_AND_ASSIGN(GpuDataManagerImpl);
 };