Update gyp/gn files after header moved from webkit to cc/blink.

cc/blink/BUILD.gn

 # 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.
 
 import("//testing/test.gni")
 
 # GYP version: //cc/blink/cc_blink.gyp:cc_blink
 component("blink") {
   output_name = "cc_blink"
 
   sources = [
+    "context_provider_web_context.h",
     "cc_blink_export.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",
@@ skipping 63 matching lines @@
       "//base/third_party/dynamic_annotations",
       "//skia",
       "//testing/gtest",
       "//ui/gfx/geometry",
       "//ui/gfx:test_support",
       "//cc",
       "//cc:test_support",
     ]
   }
 }