Put back allow_circular_includes_from in 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")
 
 # See //content/BUILD.gn for how this works.
 group("renderer") {
   if (is_component_build) {
@@ skipping 21 matching lines @@
     "//third_party/libjingle",
     "//third_party/WebKit/public:blink_headers",
     "//third_party/widevine/cdm:version_h",
     "//ui/gfx",
     "//v8",
   ]
 
   allow_circular_includes_from = [
     # This target is a pair with content/renderer. They always go together and
     # include headers from each other.
-    # TODO(brettw) enable this when this permits non-dependent targets.
-    #"//content/renderer",
+    "//content/renderer",
   ]
 
   if (enable_webrtc) {
     sources += rebase_path(
         content_renderer_gypi_values.public_renderer_webrtc_sources,
         ".", "//content")
   }
 }