Content "gn check" work.

content/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("//build/config/ui.gni")
 import("//content/renderer/renderer.gni")
 import("//media/media_options.gni")
 
 source_set("renderer") {
   # Only the public target should depend on this. All other targets (even
   # internal content ones) should depend on the public one.
-  visibility = [ "//content/public/renderer:renderer_sources" ]
+  visibility = [
+    ":for_content_tests",
+    "//content/public/renderer:renderer_sources",
+  ]
 
   sources = rebase_path(content_renderer_gypi_values.private_renderer_sources,
                         ".",
                         "//content")
 
   configs += [
     "//content:content_implementation",
     "//build/config/compiler:no_size_t_to_int_warning",
     "//content/public/common:mojo_shell_client",
   ]
   defines = []
 
+  public_deps = []
   deps = [
     "//base:i18n",
     "//cc",
     "//cc/blink",
     "//cc/proto",
     "//cc/surfaces",
     "//cc/surfaces:surface_id",
     "//components/scheduler:scheduler",
     "//components/url_formatter",
     "//content:resources",
-    "//content/common:mojo_bindings",
+    "//content/common",
     "//content/gpu:gpu_sources",
     "//content/public/child:child_sources",
     "//content/public/common:common_sources",
     "//content/public/common:feature_h264_with_openh264_ffmpeg",
     "//content/public/common:features",
     "//content/public/common:mojo_bindings",
     "//crypto:platform",
     "//device/battery:mojo_bindings",
     "//device/bluetooth",
     "//device/usb/public/interfaces",
@@ skipping 33 matching lines @@
     "//ui/events:events_base",
     "//ui/events/blink",
     "//ui/gl",
     "//ui/native_theme",
     "//ui/surface",
     "//v8",
   ]
   allow_circular_includes_from = []
 
   if (use_aura) {
-    deps += [ "//content/renderer/mus" ]
+    public_deps += [ "//content/renderer/mus" ]
     allow_circular_includes_from += [ "//content/renderer/mus" ]
   }
 
   if (is_mac) {
     sources -= [
       "webscrollbarbehavior_impl_gtkoraura.cc",
       "webscrollbarbehavior_impl_gtkoraura.h",
     ]
     sources += [
       "external_popup_menu.cc",
@@ skipping 139 matching lines @@
   }
 
   if (use_seccomp_bpf) {
     defines += [ "USE_SECCOMP_BPF" ]
   }
 
   if (use_ozone) {
     deps += [ "//ui/ozone" ]
   }
 }
+
+# See comment at the top of //content/BUILD.gn for how this works.
+group("for_content_tests") {
+  visibility = [ "//content/test/*" ]
+  if (!is_component_build) {
+    public_deps = [
+      ":renderer",
+    ]
+  }
+}