reland: mash: Remove ChromeLauncherController's |id_to_item_controller_map_|.

chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc

Index: chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
diff --git a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
index 0bcb2992e698e66a972790d111f95a21d3b5a289..b2138081f9ce64672875a2cb8b54c19fa70f5e56 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
@@ -43,12 +43,6 @@ void ChromeLauncherControllerMus::SetItemStatus(ash::ShelfID id,
   NOTIMPLEMENTED();
 }
 
-void ChromeLauncherControllerMus::SetShelfItemDelegate(
-    ash::ShelfID id,
-    std::unique_ptr<ash::ShelfItemDelegate> item_delegate) {
-  NOTIMPLEMENTED();
-}
-
 void ChromeLauncherControllerMus::CloseLauncherItem(ash::ShelfID id) {
   NOTIMPLEMENTED();
 }
@@ -175,12 +169,6 @@ ChromeLauncherControllerMus::GetBrowserShortcutLauncherItemController() {
   return nullptr;
 }
 
-ash::ShelfItemDelegate* ChromeLauncherControllerMus::GetShelfItemDelegate(
-    const ash::ShelfID id) {
-  NOTIMPLEMENTED();
-  return nullptr;
-}
-
 bool ChromeLauncherControllerMus::ShelfBoundsChangesProbablyWithUser(
     ash::WmShelf* shelf,
     const AccountId& account_id) const {