[Media Router] Adds a contextual menu item to remove the MR component action.

chrome/browser/extensions/component_migration_helper.h

Index: chrome/browser/extensions/component_migration_helper.h
diff --git a/chrome/browser/extensions/component_migration_helper.h b/chrome/browser/extensions/component_migration_helper.h
index fd9a8e3232dae4aa8fad66f5fb944aaa0f35b6bc..4f4ce9eb9cd61ff5469dbc8c6241587c948914e9 100644
--- a/chrome/browser/extensions/component_migration_helper.h
+++ b/chrome/browser/extensions/component_migration_helper.h
@@ -100,6 +100,9 @@ class ComponentMigrationHelper : public ExtensionRegistryObserver {
   // extension loading.
   void OnFeatureDisabled(const std::string& component_action_id);
 
+  // Call when the user manually removes the component action from the toolbar.
+  void OnActionRemoved(const std::string& component_action_id);
+
   // extensions::ExtensionRegistryObserver:
   void OnExtensionReady(content::BrowserContext* browser_context,
                         const Extension* extension) override;