Mark SwapBuffers for an offscreen surface as unimplemented

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 57 matching lines @@
   }
   texture_object_map.clear();
 }
 
 GLES2DecoderPassthroughImpl::GLES2DecoderPassthroughImpl(ContextGroup* group)
     : commands_to_process_(0),
       debug_marker_manager_(),
       logger_(&debug_marker_manager_),
       surface_(),
       context_(),
+      offscreen_(false),
       group_(group),
       feature_info_(group->feature_info()) {
   DCHECK(group);
 }
 
 GLES2DecoderPassthroughImpl::~GLES2DecoderPassthroughImpl() {}
 
 GLES2Decoder::Error GLES2DecoderPassthroughImpl::DoCommands(
     unsigned int num_commands,
     const volatile void* buffer,
@@ skipping 66 matching lines @@
 bool GLES2DecoderPassthroughImpl::Initialize(
     const scoped_refptr<gl::GLSurface>& surface,
     const scoped_refptr<gl::GLContext>& context,
     bool offscreen,
     const DisallowedFeatures& disallowed_features,
     const ContextCreationAttribHelper& attrib_helper) {
   // Take ownership of the context and surface. The surface can be replaced
   // with SetSurface.
   context_ = context;
   surface_ = surface;
+  offscreen_ = offscreen;
 
   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 ||
@@ skipping 675 matching lines @@
   }, /* NOLINT */
 
 const GLES2DecoderPassthroughImpl::CommandInfo
     GLES2DecoderPassthroughImpl::command_info[] = {
         GLES2_COMMAND_LIST(GLES2_CMD_OP)};
 
 #undef GLES2_CMD_OP
 
 }  // namespace gles2
 }  // namespace gpu