Clean up mac gpu switching code a little.

content/browser/gpu/gpu_data_manager_impl.h

 // Copyright (c) 2013 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 <string>
 
 #include "base/compiler_specific.h"
@@ skipping 148 matching lines @@
                           int render_process_id,
                           int render_view_id,
                           ThreeDAPIType requester);
 
   // Get number of features being blacklisted.
   size_t GetBlacklistedFeatureCount() const;
 
   void SetDisplayCount(unsigned int display_count);
   unsigned int GetDisplayCount() const;
 
+  // Set the active gpu.
+  // Return true if it's a different GPU from the previous active one.
+  bool UpdateActiveGpu(uint32 vendor_id, uint32 device_id);
+
   // Called when GPU process initialization failed.
   void OnGpuProcessInitFailure();
 
   bool IsDriverBugWorkaroundActive(int feature) const;
 
  private:
   friend class GpuDataManagerImplPrivate;
   friend class GpuDataManagerImplPrivateTest;
   friend struct DefaultSingletonTraits<GpuDataManagerImpl>;
 
@@ skipping 26 matching lines @@
 
   mutable base::Lock lock_;
   scoped_ptr<GpuDataManagerImplPrivate> private_;
 
   DISALLOW_COPY_AND_ASSIGN(GpuDataManagerImpl);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GPU_GPU_DATA_MANAGER_IMPL_H_