Updated OSX to blacklist multisampling when multiple monitors are connected

content/browser/gpu/gpu_data_manager_impl.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 CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_H_
 #define CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_H_
 
 #include <list>
 #include <map>
 #include <set>
@@ skipping 154 matching lines @@
 
   // Get number of features being blacklisted.
   size_t GetBlacklistedFeatureCount() const;
 
   typedef base::Callback<void()> GpuSwitchCallback;
 
   // Add and remove gpu switch callback.
   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;
   };
 
   typedef std::map<std::string, DomainBlockEntry> DomainBlockMap;
 
   typedef ObserverListThreadSafe<GpuDataManagerObserver>
       GpuDataManagerObserverList;
 
@@ skipping 99 matching lines @@
 
   // Number of currently open windows, to be used in gpu memory allocation.
   int window_count_;
 
   DomainBlockMap blocked_domains_;
   mutable std::list<base::Time> timestamps_of_gpu_resets_;
   bool domain_blocking_enabled_;
 
   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);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_H_