Fix EXT_draw_buffers detection on some GL ES 3 contexts

gpu/command_buffer/service/context_group.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/context_group.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 102 matching lines @@
     DCHECK(feature_info_);
     if (!mailbox_manager_.get())
       mailbox_manager_ = new MailboxManagerImpl;
     transfer_buffer_manager_ = new TransferBufferManager(memory_tracker_.get());
   }
 }
 
 bool ContextGroup::Initialize(GLES2Decoder* decoder,
                               ContextType context_type,
                               const DisallowedFeatures& disallowed_features) {
-  if (!gpu_preferences_.enable_es3_apis &&
-      (context_type == CONTEXT_TYPE_OPENGLES3 ||
-       context_type == CONTEXT_TYPE_WEBGL2)) {
+  bool enable_es3 = context_type == CONTEXT_TYPE_OPENGLES3 ||
+                    context_type == CONTEXT_TYPE_WEBGL2;
+  if (!gpu_preferences_.enable_es3_apis && enable_es3) {
     DLOG(ERROR) << "ContextGroup::Initialize failed because ES3 APIs are "
                 << "not available.";
     return false;
   }
   if (HaveContexts()) {
     if (context_type != feature_info_->context_type()) {
       DLOG(ERROR) << "ContextGroup::Initialize failed because the type of "
                   << "the context does not fit with the group.";
       return false;
     }
@@ skipping 27 matching lines @@
   if (feature_info_->feature_flags().chromium_framebuffer_multisample ||
       feature_info_->feature_flags().multisampled_render_to_texture) {
     if (feature_info_->feature_flags(
             ).use_img_for_multisampled_render_to_texture) {
       glGetIntegerv(GL_MAX_SAMPLES_IMG, &max_samples);
     } else {
       glGetIntegerv(GL_MAX_SAMPLES, &max_samples);
     }
   }
 
-  if (feature_info_->feature_flags().ext_draw_buffers) {
+  if (enable_es3 || feature_info_->feature_flags().ext_draw_buffers) {
     GetIntegerv(GL_MAX_COLOR_ATTACHMENTS_EXT, &max_color_attachments_);
     if (max_color_attachments_ < 1)
       max_color_attachments_ = 1;
     if (max_color_attachments_ > 16)
       max_color_attachments_ = 16;
     GetIntegerv(GL_MAX_DRAW_BUFFERS_ARB, &max_draw_buffers_);
     if (max_draw_buffers_ < 1)
       max_draw_buffers_ = 1;
     if (max_draw_buffers_ > 16)
       max_draw_buffers_ = 16;
@@ skipping 444 matching lines @@
     GLuint client_id, GLuint* service_id) const {
   Buffer* buffer = buffer_manager_->GetBuffer(client_id);
   if (!buffer)
     return false;
   *service_id = buffer->service_id();
   return true;
 }
 
 }  // namespace gles2
 }  // namespace gpu