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

ui/app_list/app_list_item_model.cc

Index: ui/app_list/app_list_item_model.cc
diff --git a/ui/app_list/app_list_item_model.cc b/ui/app_list/app_list_item_model.cc
index c3a74bfee59a5fc881720167a2544112cf863b36..c9a28315dcce27ea0e2a6b063643d5656aed0c54 100644
--- a/ui/app_list/app_list_item_model.cc
+++ b/ui/app_list/app_list_item_model.cc
@@ -9,7 +9,10 @@
 
 namespace app_list {
 
-AppListItemModel::AppListItemModel() : highlighted_(false) {
+AppListItemModel::AppListItemModel()
+    : highlighted_(false),
+      is_installing_(false),
+      percent_downloaded_(-1) {
 }
 
 AppListItemModel::~AppListItemModel() {
@@ -38,6 +41,26 @@ void AppListItemModel::SetHighlighted(bool highlighted) {
                     ItemHighlightedChanged());
 }
 
+void AppListItemModel::SetIsInstalling(bool is_installing) {
+  if (is_installing_ == is_installing)
+    return;
+
+  is_installing_ = is_installing;
+  FOR_EACH_OBSERVER(AppListItemModelObserver,
+                    observers_,
+                    ItemIsInstallingChanged());
+}
+
+void AppListItemModel::SetPercentDownloaded(int percent_downloaded) {
+  if (percent_downloaded_ == percent_downloaded)
+    return;
+
+  percent_downloaded_ = percent_downloaded;
+  FOR_EACH_OBSERVER(AppListItemModelObserver,
+                    observers_,
+                    ItemPercentDownloadedChanged());
+}
+
 void AppListItemModel::AddObserver(AppListItemModelObserver* observer) {
   observers_.AddObserver(observer);
 }