Force GPU switch with CGLSetVirtualScreen only for compositor

gpu/command_buffer/service/gles2_cmd_decoder.cc

 // 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.
 
 #include "gpu/command_buffer/service/gles2_cmd_decoder.h"
 
 #include <stdio.h>
 
 #include <algorithm>
 #include <list>
@@ skipping 2555 matching lines @@
 
   DoBindBuffer(GL_ARRAY_BUFFER, 0);
   DoBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
   DoBindFramebuffer(GL_FRAMEBUFFER, 0);
   DoBindRenderbuffer(GL_RENDERBUFFER, 0);
 
   if (feature_info_->workarounds().reverse_point_sprite_coord_origin) {
     glPointParameteri(GL_POINT_SPRITE_COORD_ORIGIN, GL_LOWER_LEFT);
   }
 
+  // Only compositor contexts are known to use only the subset of GL
+  // that can be safely migrated between the iGPU and the dGPU. Mark
+  // those contexts as safe to forcibly transition between the GPUs.
+  // http://crbug.com/180876, http://crbug.com/227228
+  if (!offscreen)
+    context_->SetSafeToForceGpuSwitch();
+
   // Create a delegate to perform async pixel transfers.
   async_pixel_transfer_delegate_ =
       gfx::AsyncPixelTransferDelegate::Create(context.get());
 
   return true;
 }
 
 void GLES2DecoderImpl::UpdateCapabilities() {
   util_.set_num_compressed_texture_formats(
       validators_->compressed_texture_format.GetValues().size());
@@ skipping 7947 matching lines @@
   return error::kNoError;
 }
 
 // Include the auto-generated part of this file. We split this because it means
 // we can easily edit the non-auto generated parts right here in this file
 // instead of having to edit some template or the code generator.
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu