[win] Add a progress bar in the app launcher for app installs.

chrome/browser/ui/app_list/extension_app_item.cc

Index: chrome/browser/ui/app_list/extension_app_item.cc
diff --git a/chrome/browser/ui/app_list/extension_app_item.cc b/chrome/browser/ui/app_list/extension_app_item.cc
index b23a368479d7ffeadc98776fd53f4e232173bf2b..7bb4d1fb4fed0e05c46e764069012d8d9b618b5a 100644
--- a/chrome/browser/ui/app_list/extension_app_item.cc
+++ b/chrome/browser/ui/app_list/extension_app_item.cc
@@ -208,8 +208,9 @@ bool ExtensionAppItem::HasOverlay() const {
 
 void ExtensionAppItem::Reload() {
   const Extension* extension = GetExtension();
-  // If the extension isn't there, show the 'extension is installing' UI.
-  if (!extension) {
+  bool is_installing = !extension;
+  SetIsInstalling(is_installing);
+  if (is_installing) {
     SetTitle(extension_name_);
     UpdateIcon();
     return;