Run the WebGL conformance tests with the passthrough command decoder.

gpu/command_buffer/service/gles2_cmd_decoder_passthrough.cc

 // Copyright (c) 2016 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_passthrough.h"
 
 #include "gpu/command_buffer/service/feature_info.h"
 #include "gpu/command_buffer/service/gl_utils.h"
 #include "ui/gl/gl_version_info.h"
 
@@ skipping 153 matching lines @@
 
   if (!group_->Initialize(this, attrib_helper.context_type,
                           disallowed_features)) {
     group_ = NULL;  // Must not destroy ContextGroup if it is not initialized.
     Destroy(true);
     return false;
   }
 
   // Check for required extensions
   if (!feature_info_->feature_flags().angle_robust_client_memory ||
-      !feature_info_->feature_flags().chromium_bind_generates_resource ||
-      (feature_info_->IsWebGLContext() !=
-       feature_info_->feature_flags().angle_webgl_compatibility)) {
+      !feature_info_->feature_flags().chromium_bind_generates_resource) {
+    // TODO(geofflang): Verify that ANGLE_webgl_compatibility is enabled if this
+    // is a WebGL context (depends on crbug.com/671217).
     Destroy(true);
     return false;
   }
 
   image_manager_.reset(new ImageManager());
 
   bind_generates_resource_ = group_->bind_generates_resource();
 
   resources_ = group_->passthrough_resources();
 
@@ skipping 653 matching lines @@
   }, /* NOLINT */
 
 const GLES2DecoderPassthroughImpl::CommandInfo
     GLES2DecoderPassthroughImpl::command_info[] = {
         GLES2_COMMAND_LIST(GLES2_CMD_OP)};
 
 #undef GLES2_CMD_OP
 
 }  // namespace gles2
 }  // namespace gpu