Use NV_draw_buffers to implement EXT_draw_buffers

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 2774 matching lines @@
   resources.FragmentPrecisionHigh =
       PrecisionMeetsSpecForHighpFloat(range[0], range[1], precision);
 
   if (force_webgl_glsl_validation_) {
     resources.OES_standard_derivatives = derivatives_explicitly_enabled_;
     resources.EXT_frag_depth = frag_depth_explicitly_enabled_;
     resources.EXT_draw_buffers = draw_buffers_explicitly_enabled_;
     if (!draw_buffers_explicitly_enabled_)
       resources.MaxDrawBuffers = 1;
     resources.EXT_shader_texture_lod = shader_texture_lod_explicitly_enabled_;
+    resources.NV_draw_buffers =
+        draw_buffers_explicitly_enabled_ && features().nv_draw_buffers;
   } else {
     resources.OES_standard_derivatives =
         features().oes_standard_derivatives ? 1 : 0;
     resources.ARB_texture_rectangle =
         features().arb_texture_rectangle ? 1 : 0;
     resources.OES_EGL_image_external =
         features().oes_egl_image_external ? 1 : 0;
     resources.EXT_draw_buffers =
         features().ext_draw_buffers ? 1 : 0;
     resources.EXT_frag_depth =
         features().ext_frag_depth ? 1 : 0;
     resources.EXT_shader_texture_lod =
         features().ext_shader_texture_lod ? 1 : 0;
+    resources.NV_draw_buffers =
+        features().nv_draw_buffers ? 1 : 0;
   }
 
   ShShaderSpec shader_spec = force_webgl_glsl_validation_ ? SH_WEBGL_SPEC
                                                           : SH_GLES2_SPEC;
   if (shader_spec == SH_WEBGL_SPEC && features().enable_shader_name_hashing)
     resources.HashFunction = &CityHash64;
   else
     resources.HashFunction = NULL;
   ShaderTranslatorInterface::GlslImplementationType implementation_type =
       gfx::GetGLImplementation() == gfx::kGLImplementationEGLGLES2 ?
@@ skipping 8326 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 "gpu/command_buffer/service/gles2_cmd_decoder_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu