Start work on adding content/browser to GN build.

content/public/renderer/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("//build/config/features.gni")
 import("//content/renderer/renderer.gni")
 
 source_set("renderer") {
   sources = rebase_path(content_renderer_gypi_values.public_renderer_sources,
                         ".", "//content")
 
   configs += [
-    "//content:blink_headers_stub_config",
     "//content:content_implementation",
     "//content:libjingle_stub_config",
     "//content:v8_stub_config",
     "//content:widevine_stub_config",
   ]
 
   deps = [
     "//content/renderer",
     "//skia",
+    "//third_party/WebKit/public:blink_headers",
   ]
 
   if (enable_webrtc) {
     sources += rebase_path(
         content_renderer_gypi_values.public_renderer_webrtc_sources,
         ".", "//content")
   }
 }