Revert of 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 b2138081f9ce64672875a2cb8b54c19fa70f5e56..0bcb2992e698e66a972790d111f95a21d3b5a289 100644
--- a/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
+++ b/chrome/browser/ui/ash/launcher/chrome_launcher_controller_mus.cc
@@ -43,6 +43,12 @@
   NOTIMPLEMENTED();
 }
 
+void ChromeLauncherControllerMus::SetShelfItemDelegate(
+    ash::ShelfID id,
+    std::unique_ptr<ash::ShelfItemDelegate> item_delegate) {
+  NOTIMPLEMENTED();
+}
+
 void ChromeLauncherControllerMus::CloseLauncherItem(ash::ShelfID id) {
   NOTIMPLEMENTED();
 }
@@ -165,6 +171,12 @@
 
 BrowserShortcutLauncherItemController*
 ChromeLauncherControllerMus::GetBrowserShortcutLauncherItemController() {
+  NOTIMPLEMENTED();
+  return nullptr;
+}
+
+ash::ShelfItemDelegate* ChromeLauncherControllerMus::GetShelfItemDelegate(
+    const ash::ShelfID id) {
   NOTIMPLEMENTED();
   return nullptr;
 }