Pass initial size and GPU preference via context attributes

components/mus/gles2/command_buffer_driver.cc

Index: components/mus/gles2/command_buffer_driver.cc
diff --git a/components/mus/gles2/command_buffer_driver.cc b/components/mus/gles2/command_buffer_driver.cc
index b3821b9f4dec1acc7f5489955097dfc64cdf761a..1c35904e9f63b9c82b844f72b8a857216ec735bc 100644
--- a/components/mus/gles2/command_buffer_driver.cc
+++ b/components/mus/gles2/command_buffer_driver.cc
@@ -83,6 +83,7 @@ bool CommandBufferDriver::Initialize(
   gpu::gles2::ContextCreationAttribHelper attrib_helper;
   if (!attrib_helper.Parse(attribs.storage()))
     return false;
+  // TODO(piman): attribs can't currently represent gpu_preference.
 
   const bool offscreen = widget_ == gfx::kNullAcceleratedWidget;
   if (offscreen) {
@@ -116,9 +117,9 @@ bool CommandBufferDriver::Initialize(
   if (!surface_.get())
     return false;
 
-  // TODO(piman): virtual contexts, gpu preference.
-  context_ = gl::init::CreateGLContext(gpu_state_->share_group(),
-                                       surface_.get(), gl::PreferIntegratedGpu);
+  // TODO(piman): virtual contexts.
+  context_ = gl::init::CreateGLContext(
+      gpu_state_->share_group(), surface_.get(), attrib_helper.gpu_preference);
   if (!context_.get())
     return false;
 
@@ -161,8 +162,8 @@ bool CommandBufferDriver::Initialize(
 
   gpu::gles2::DisallowedFeatures disallowed_features;
 
-  if (!decoder_->Initialize(surface_, context_, offscreen, gfx::Size(1, 1),
-                            disallowed_features, attrib_helper))
+  if (!decoder_->Initialize(surface_, context_, offscreen, disallowed_features,
+                            attrib_helper))
     return false;
 
   command_buffer_->SetPutOffsetChangeCallback(base::Bind(