ash: Remove ShelfModel id conversion functions.

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

Index: chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc
diff --git a/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc b/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc
index 94415afc6194159266755ec0117ec7f4db913e98..cf68de22e4f96d02deaeecb35d6d9a8f429f5960 100644
--- a/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc
+++ b/chrome/browser/ui/ash/launcher/extension_launcher_context_menu.cc
@@ -94,8 +94,7 @@ void ExtensionLauncherContextMenu::Init() {
   }
   AddSeparator(ui::NORMAL_SEPARATOR);
   if (item().type == ash::TYPE_PINNED_APP || item().type == ash::TYPE_APP) {
-    const extensions::MenuItem::ExtensionKey app_key(
-        controller()->GetAppIDForShelfID(item().id));

[James Cook, 2017/05/10 15:56:34]

Global praise: It's so awesome we don't have to do these lookups all over the
place anymore.

[msw, 2017/05/10 18:21:54]

I agree!

+    const extensions::MenuItem::ExtensionKey app_key(item().id.app_id);
     if (!app_key.empty()) {
       int index = 0;
       extension_items_->AppendExtensionItems(app_key, base::string16(), &index,