Add a version of gpu_fuzzer that is backed by the NULL ANGLE backend

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 4767 matching lines @@
   offscreen_target_frame_buffer_.reset();
   offscreen_target_color_texture_.reset();
   offscreen_target_color_render_buffer_.reset();
   offscreen_target_depth_render_buffer_.reset();
   offscreen_target_stencil_render_buffer_.reset();
   offscreen_saved_frame_buffer_.reset();
   offscreen_saved_color_texture_.reset();
   offscreen_resolved_frame_buffer_.reset();
   offscreen_resolved_color_texture_.reset();
 
+  // Release all fences now, because some fence types need the context to be
+  // current on destruction.
+  pending_readpixel_fences_ = std::queue<FenceCallback>();
+
   // Need to release these before releasing |group_| which may own the
   // ShaderTranslatorCache.
   fragment_translator_ = NULL;
   vertex_translator_ = NULL;
 
   // Destroy the GPU Tracer which may own some in process GPU Timings.
   if (gpu_tracer_) {
     gpu_tracer_->Destroy(have_context);
     gpu_tracer_.reset();
   }
@@ skipping 14074 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