Revert of current program can be null in ES2/ES3 contexts.

gpu/command_buffer/service/context_state.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_state.h"
 
 #include <stddef.h>
 
 #include <cmath>
 
@@ skipping 204 matching lines @@
 
 ContextState::ContextState(FeatureInfo* feature_info,
                            ErrorStateClient* error_state_client,
                            Logger* logger)
     : active_texture_unit(0),
       bound_renderbuffer_valid(false),
       pack_reverse_row_order(false),
       ignore_cached_state(false),
       fbo_binding_for_scissor_workaround_dirty(false),
       framebuffer_srgb_(false),
+      max_vertex_attribs_(0),
       feature_info_(feature_info),
       error_state_(ErrorState::Create(error_state_client, logger)) {
   Initialize();
 }
 
 ContextState::~ContextState() {
 }
 
 void ContextState::RestoreTextureUnitBindings(
     GLuint unit, const ContextState* prev_state) const {
@@ skipping 467 matching lines @@
   UpdateUnpackParameters();
 }
 
 // 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/context_state_impl_autogen.h"
 
 }  // namespace gles2
 }  // namespace gpu