Merge 193302 "Force GPU switch with CGLSetVirtualScreen only for..."

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
===================================================================
--- gpu/command_buffer/service/gles2_cmd_decoder.cc	(revision 194412)
+++ gpu/command_buffer/service/gles2_cmd_decoder.cc	(working copy)
@@ -2574,6 +2574,13 @@
     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());