Revert of Pass initial size and GPU preference via context attributes

gpu/command_buffer/common/gles2_cmd_utils.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.
 
 // This file is here so other GLES2 related files can have a common set of
 // includes where appropriate.
 
 #include <sstream>
 #include <GLES2/gl2.h>
 #include <GLES2/gl2ext.h>
@@ skipping 1771 matching lines @@
 // Chromium only.
 const int32_t kBindGeneratesResource = 0x10000;
 const int32_t kFailIfMajorPerfCaveat = 0x10001;
 const int32_t kLoseContextWhenOutOfMemory = 0x10002;
 const int32_t kShouldUseNativeGMBForBackbuffer = 0x10003;
 const int32_t kContextType = 0x10004;
 
 }  // namespace
 
 ContextCreationAttribHelper::ContextCreationAttribHelper()
-    : gpu_preference(gl::PreferIntegratedGpu),
-      alpha_size(-1),
+    : alpha_size(-1),
       blue_size(-1),
       green_size(-1),
       red_size(-1),
       depth_size(-1),
       stencil_size(-1),
       samples(-1),
       sample_buffers(-1),
       buffer_preserved(true),
       bind_generates_resource(true),
       fail_if_major_perf_caveat(false),
@@ skipping 71 matching lines @@
   }
 
   return true;
 }
 
 #include "gpu/command_buffer/common/gles2_cmd_utils_implementation_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu