Update from https://crrev.com/318214

cc/blink/cc_blink.gyp

 # Copyright 2014 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.
 
 {
   'targets': [
     {
       # GN version: //cc/blink
       'target_name': 'cc_blink',
       'type': '<(component)',
       'dependencies': [
         '../../gpu/gpu.gyp:command_buffer_common',
         '../../base/base.gyp:base',
         '../../third_party/WebKit/public/blink.gyp:blink',
         '../../skia/skia.gyp:skia',
         '../cc.gyp:cc',
         '../../ui/gfx/gfx.gyp:gfx',
         '../../ui/gfx/gfx.gyp:gfx_geometry',
       ],
       'defines': [
         'CC_BLINK_IMPLEMENTATION',
       ],
       'export_dependent_settings': [
         '../../skia/skia.gyp:skia',
       ],
       # This sources list is duplicated in //cc/blink/BUILD.gn
       'sources': [
         'cc_blink_export.h',
+        'context_provider_web_context.h',
         'scrollbar_impl.cc',
         'scrollbar_impl.h',
         'web_animation_curve_common.cc',
         'web_animation_curve_common.h',
         'web_animation_impl.cc',
         'web_animation_impl.h',
         'web_compositor_support_impl.cc',
         'web_compositor_support_impl.h',
         'web_content_layer_impl.cc',
         'web_content_layer_impl.h',
@@ skipping 24 matching lines @@
         'web_to_cc_animation_delegate_adapter.cc',
         'web_to_cc_animation_delegate_adapter.h',
         'web_transform_animation_curve_impl.cc',
         'web_transform_animation_curve_impl.h',
         'web_transform_operations_impl.cc',
         'web_transform_operations_impl.h',
       ],
     },
   ]
 }