Force GPU switch with CGLSetVirtualScreen only for compositor

ui/gl/gl_context.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_GL_CONTEXT_H_
 #define UI_GL_GL_CONTEXT_H_
 
 #include <string>
 
 #include "base/basictypes.h"
@@ skipping 43 matching lines @@
   virtual void SetSwapInterval(int interval) = 0;
 
   // Returns space separated list of extensions. The context must be current.
   virtual std::string GetExtensions();
 
   // Returns in bytes the total amount of GPU memory for the GPU which this
   // context is currently rendering on. Returns false if no extension exists
   // to get the exact amount of GPU memory.
   virtual bool GetTotalGpuMemory(size_t* bytes);
 
+  // Indicate that it is safe to force this context to switch GPUs, since
+  // transitioning can cause corruption and hangs (OS X only).
+  virtual void SetSafeToForceGpuSwitch();
+
   // Returns whether the current context supports the named extension. The
   // context must be current.
   bool HasExtension(const char* name);
 
   GLShareGroup* share_group();
 
   // Create a GL context that is compatible with the given surface.
   // |share_group|, if non-NULL, is a group of contexts which the
   // internally created OpenGL context shares textures and other resources.
   static scoped_refptr<GLContext> CreateGLContext(
@@ skipping 34 matching lines @@
 
   scoped_refptr<GLShareGroup> share_group_;
   scoped_ptr<VirtualGLApi> virtual_gl_api_;
 
   DISALLOW_COPY_AND_ASSIGN(GLContext);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GL_GL_CONTEXT_H_