Remove enable_media_router.

chrome/browser/about_flags.cc

Index: chrome/browser/about_flags.cc
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 86e7c646467e0a1408db3ac108e238bebacd8010..2b73bfe60ff38285f7f6faddc76abbd828c810fd 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -1842,7 +1842,7 @@ const FeatureEntry kFeatureEntries[] = {
      SINGLE_VALUE_TYPE_AND_VALUE(
          switches::kSyncServiceURL,
          "https://chrome-sync.sandbox.google.com/chrome-sync/alpha")},
-#if defined(ENABLE_MEDIA_ROUTER) && !defined(OS_ANDROID)
+#if !defined(OS_ANDROID)
     {"load-media-router-component-extension",
      flag_descriptions::kLoadMediaRouterComponentExtensionName,
      flag_descriptions::kLoadMediaRouterComponentExtensionDescription,
@@ -1852,7 +1852,7 @@ const FeatureEntry kFeatureEntries[] = {
          "1",
          switches::kLoadMediaRouterComponentExtension,
          "0")},
-#endif  // ENABLE_MEDIA_ROUTER && !OS_ANDROID
+#endif  // !OS_ANDROID
 // Since Drive Search is not available when app list is disabled, flag guard
 // enable-drive-search-in-chrome-launcher flag.
 #if BUILDFLAG(ENABLE_APP_LIST)