media: Use "public_configs" for "mojo_media_config"

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 = [
     ":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 = []
+  public_configs = []
 
-  public_deps = []
   deps = [
     "//base:i18n",
     "//cc",
     "//cc/blink",
     "//cc/proto",
     "//cc/surfaces",
     "//cc/surfaces:surface_id",
     "//components/scheduler:scheduler",
     "//components/url_formatter",
     "//content:resources",
@@ skipping 183 matching lines @@
   }
 
   if (enable_mojo_media) {
     sources += [
       "media/media_interface_provider.cc",
       "media/media_interface_provider.h",
     ]
 
     deps += [
       "//media/mojo/interfaces",
+
+      # Defines in mojo_media_config are also pulled in here.
       "//media/mojo/services:proxy",
     ]
   }
 
   if (enable_webvr) {
     sources += [
       "vr/vr_dispatcher.cc",
       "vr/vr_dispatcher.h",
       "vr/vr_type_converters.cc",
       "vr/vr_type_converters.h",
     ]
   }
 
   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 (enable_mojo_media) {
+    # For the defines in mojo_media_config.
+    public_configs = [ "//media/mojo/services:mojo_media_config" ]

[xhwang, 2016/03/28 21:34:33]

Adding this to the "renderer" target doesn't work because tests are depending on
this "for_content_tests" target directly. It looks odd to add a public_configs
here but it works.

+  }
+
   if (!is_component_build) {
     public_deps = [
       ":renderer",
     ]
   }
 }