Create MediaRouterActionController and MediaRouterUIService

chrome/browser/extensions/component_migration_helper.cc

Index: chrome/browser/extensions/component_migration_helper.cc
diff --git a/chrome/browser/extensions/component_migration_helper.cc b/chrome/browser/extensions/component_migration_helper.cc
index 7de2caa9773e3e49033483107317284b888d23b4..7e42c45d350bc480b92d31cdb6cc891ae2f318cb 100644
--- a/chrome/browser/extensions/component_migration_helper.cc
+++ b/chrome/browser/extensions/component_migration_helper.cc
@@ -139,6 +139,16 @@ void ComponentMigrationHelper::OnExtensionReady(
   }
 }
 
+bool ComponentMigrationHelper::GetComponentActionPref(

[mark a. foltz, 2016/09/13 18:23:04]

- Please refactor @L80 to call this method.
- DCHECK() the success value from GetBoolean as is done above.

[takumif, 2016/09/14 04:00:51]

Done. DCHECKing here means component actions can only call this when the pref
exists for the action, and that should be okay (at least for MRA) since
MRUIService wouldn't be instantiated if MR is disabled, and OnFeatureDisabled()
(which removes prefs) only gets called when starting up ToolbarActionsModel.

+    const std::string& component_action_id) const {
+  const base::DictionaryValue* migration_pref = pref_service_->GetDictionary(
+      ::prefs::kToolbarMigratedComponentActionStatus);
+  bool component_action_pref = false;
+
+  migration_pref->GetBoolean(component_action_id, &component_action_pref);

[mark a. foltz, 2016/09/13 18:23:04]

What does this return if there is no pre-existing value for
|component_action_id| in |migration_pref|?

[takumif, 2016/09/14 04:00:51]

GetBoolean returns false and not touch |component_action_pref| in that case.
https://cs.chromium.org/chromium/src/base/values.cc?sq=package:chromium&rcl=1...

+  return component_action_pref;
+}
+
 void ComponentMigrationHelper::SetComponentActionPref(
     const std::string& component_action_id,
     bool enabled) {