Add workaround for Mac stencil buffer leak

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 <limits.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdio.h>
@@ skipping 3769 matching lines @@
   caps.iosurface = true;
 #endif
 
   caps.post_sub_buffer = supports_post_sub_buffer_;
   caps.swap_buffers_with_bounds = supports_swap_buffers_with_bounds_;
   caps.commit_overlay_planes = supports_commit_overlay_planes_;
   caps.surfaceless = surfaceless_;
   bool is_offscreen = !!offscreen_target_frame_buffer_.get();
   caps.flips_vertically = !is_offscreen && surface_->FlipsVertically();
   caps.msaa_is_slow = workarounds().msaa_is_slow;
+  caps.avoid_stencil_buffers = workarounds().avoid_stencil_buffers;
   caps.dc_layers = supports_dc_layers_;
 
   caps.blend_equation_advanced =
       feature_info_->feature_flags().blend_equation_advanced;
   caps.blend_equation_advanced_coherent =
       feature_info_->feature_flags().blend_equation_advanced_coherent;
   caps.texture_rg = feature_info_->feature_flags().ext_texture_rg;
   caps.texture_norm16 = feature_info_->feature_flags().ext_texture_norm16;
   caps.texture_half_float_linear =
       feature_info_->feature_flags().enable_texture_half_float_linear;
@@ skipping 15860 matching lines @@
 }
 
 // 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 "base/macros.h"
 #include "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu