Refine dual-GPU detection on Mac OS X.

ui/gl/gpu_switching_manager.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 UI_GL_GPU_SWITCHING_MANAGER_H_
 #define UI_GL_GPU_SWITCHING_MANAGER_H_
 
 #include <vector>
 
 #include "base/memory/singleton.h"
@@ skipping 18 matching lines @@
   // If no GPU is forced, return the original GpuPreference; otherwise, return
   // the forced GPU.
   gfx::GpuPreference AdjustGpuPreference(gfx::GpuPreference gpu_preference);
 
   // In the browser process, the value for this flag is computed the first time
   // this function is called.
   // In the GPU process, the value is passed from the browser process using the
   // --supports-dual-gpus commandline switch.
   bool SupportsDualGpus();
 
-  void SetGpuCount(size_t gpu_count);
+  // Sets the vendor IDs of the GPUs on the system. The length of this
+  // vector defines the count of GPUs.
+  void SetGpuVendorIds(const std::vector<uint32>& vendor_ids);
 
   void AddObserver(GpuSwitchingObserver* observer);
   void RemoveObserver(GpuSwitchingObserver* observer);
 
   // Called when a GPU switch is noticed by the system. In the browser process
   // this is occurs as a result of a system observer. In the GPU process, this
   // occurs as a result of an IPC from the browser. The system observer is kept
   // in the browser process only so that any workarounds or blacklisting can
   // be applied there.
   void NotifyGpuSwitched();
 
  private:
   friend struct DefaultSingletonTraits<GpuSwitchingManager>;
 
   GpuSwitchingManager();
   virtual ~GpuSwitchingManager();
 
 #if defined(OS_MACOSX)
   void SwitchToDiscreteGpuMac();
 #endif  // OS_MACOSX
 
   gfx::GpuPreference gpu_switching_option_;
   bool gpu_switching_option_set_;
 
+  std::vector<uint32> vendor_ids_;
+
   bool supports_dual_gpus_;
   bool supports_dual_gpus_set_;
 
-  size_t gpu_count_;
-
   struct PlatformSpecific;
   scoped_ptr<PlatformSpecific> platform_specific_;
 
   ObserverList<GpuSwitchingObserver> observer_list_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuSwitchingManager);
 };
 
 }  // namespace ui
 
 #endif  // UI_GL_GPU_SWITCHING_MANAGER_H_