gn BUILD fixes for disabling enable_extensions and use_ash feature flags.

chrome/browser/media/router/BUILD.gn

 # Copyright 2015 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("//mojo/public/tools/bindings/mojom.gni")
 import("//testing/test.gni")
 
 gypi_values = exec_script("//build/gypi_to_gn.py",
                           [ rebase_path("media_router.gypi") ],
                           "scope",
                           [ "media_router.gypi" ])
 
 static_library("router") {
   deps = [
     "//base",
     "//chrome/common:constants",
     "//components/keyed_service/content",
     "//components/keyed_service/core",
     "//content/public/browser",
     "//url",
   ]
   sources = rebase_path(gypi_values.media_router_sources,
                         ".",
                         "//chrome/browser/media/router")
   if (!is_android) {
     deps += [
       ":mojo_bindings",
-      "//extensions/browser",
       "//mojo/public/cpp/bindings",
     ]
+    if (enable_extensions) {
+      deps += [ "//extensions/browser" ]
+    }
     sources += rebase_path(gypi_values.media_router_non_android_sources,
                            ".",
                            "//chrome/browser/media/router")
   }
 }
 
 mojom("mojo_bindings") {
   sources = [
     "mojo/media_router.mojom",
   ]
 }
 
 source_set("test_support") {
   testonly = true
   deps = [
     ":router",
     "//chrome/test:test_support",
     "//testing/gmock",
   ]
   sources = rebase_path(gypi_values.media_router_test_support_sources,
                         ".",
                         "//chrome/browser/media/router")
   if (!is_android) {
-    deps += [
-      ":mojo_bindings",
-      "//extensions/common",
-    ]
+    deps += [ ":mojo_bindings" ]
+    if (enable_extensions) {
+      deps += [ "//extensions/common" ]
+    }
     sources +=
         rebase_path(gypi_values.media_router_non_android_test_support_sources,
                     ".",
                     "//chrome/browser/media/router")
   }
 }