Migrate the pref to always show the Cast icon

chrome/browser/prefs/browser_prefs.cc

Index: chrome/browser/prefs/browser_prefs.cc
diff --git a/chrome/browser/prefs/browser_prefs.cc b/chrome/browser/prefs/browser_prefs.cc
index c71e8947b44bfd7c0774b7a27c0dfa33370beb03..5333417a0e3bd9f3cf3fa6cc43b903c89f79ffa2 100644
--- a/chrome/browser/prefs/browser_prefs.cc
+++ b/chrome/browser/prefs/browser_prefs.cc
@@ -137,6 +137,9 @@
 #include "chrome/browser/ui/webui/extensions/extension_settings_handler.h"
 #include "extensions/browser/api/runtime/runtime_api.h"
 #include "extensions/browser/extension_prefs.h"
+#if defined(ENABLE_MEDIA_ROUTER)
+#include "chrome/browser/ui/toolbar/component_toolbar_actions_factory.h"
+#endif  // defined(ENABLE_MEDIA_ROUTER)
 #endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
 #if BUILDFLAG(ENABLE_PLUGIN_INSTALLATION)
@@ -748,8 +751,24 @@ void MigrateObsoleteProfilePrefs(Profile* profile) {
 
 #if BUILDFLAG(ENABLE_EXTENSIONS)
   // Added 2/2017.
-  profile_prefs->ClearPref(kToolbarMigratedComponentActionStatus);
-#endif
+  // NOTE(takumif): When removing this code, also remove the following tests:
+  //  - MediaRouterUIBrowserTest.MigrateToolbarIconShownPref
+  //  - MediaRouterUIBrowserTest.MigrateToolbarIconUnshownPref
+  {
+#if defined(ENABLE_MEDIA_ROUTER)
+    bool show_cast_icon = false;
+    const base::DictionaryValue* action_migration_dict =
+        profile_prefs->GetDictionary(kToolbarMigratedComponentActionStatus);
+    if (action_migration_dict &&
+        action_migration_dict->GetBoolean(
+            ComponentToolbarActionsFactory::kMediaRouterActionId,
+            &show_cast_icon)) {
+      profile_prefs->SetBoolean(prefs::kShowCastIconInToolbar, show_cast_icon);
+    }
+#endif  // defined(ENABLE_MEDIA_ROUTER)
+    profile_prefs->ClearPref(kToolbarMigratedComponentActionStatus);
+  }
+#endif  // BUILDFLAG(ENABLE_EXTENSIONS)
 
   // Added 2/2017.
   {