Start work on adding content/browser to GN build.

content/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("//tools/grit/grit_rule.gni")
 
 # Applied by targets internal to content.
 config("content_implementation") {
   defines = [ "CONTENT_IMPLEMENTATION" ]
 }
 
 grit("resources") {
   source = "content_resources.grd"
 }
 
 # Stubs ------------------------------------------------------------------------
 
-# TODO(brettw) remove this and add a proper dependency on blink once that
-# target has been converted to GN. This config sets up the include directories
-# so content can compile in the meantime.
-#
-# This corresponds to third_party/WebKit/public/blink_headers.gyp:blink_headers
-config("blink_headers_stub_config") {
-  include_dirs = [ "//third_party/WebKit" ]
-}
-
 # TODO(brettw) remove this and add a proper dependency on libjingle once that
 # target has been converted to GN. This config sets up the include directories
 # so content can compile in the meantime.
 config("libjingle_stub_config") {
   include_dirs = [
     "//third_party/libjingle/overrides",
     "//third_party/libjingle/source",
     "//third_party/libyuv/include",
     "//third_party/usrsctp",
 
@@ skipping 33 matching lines @@
 # This config is a placeholder to set up the V8 include path while the V8 GN
 # build is being worked on.
 config("v8_stub_config") {
   include_dirs = [ "//v8/include" ]
 }
 
 config("widevine_stub_config") {
   # The real implementation does a copy rule to copy the header to the gen dir.
   include_dirs = [ "//third_party/widevine/cdm" ]
 }