Experimental app list: "All apps" button has a folder-like icon.

ui/app_list/views/all_apps_tile_item_view.cc

Index: ui/app_list/views/all_apps_tile_item_view.cc
diff --git a/ui/app_list/views/all_apps_tile_item_view.cc b/ui/app_list/views/all_apps_tile_item_view.cc
index acb527b1bf6d12d4eb5a180b28a68a134fcf90e1..c6e0ab51ec20790cffca4326c0b96dc393824f64 100644
--- a/ui/app_list/views/all_apps_tile_item_view.cc
+++ b/ui/app_list/views/all_apps_tile_item_view.cc
@@ -10,13 +10,19 @@
 
 namespace app_list {
 
-AllAppsTileItemView::AllAppsTileItemView(ContentsView* contents_view)
-    : contents_view_(contents_view) {
+AllAppsTileItemView::AllAppsTileItemView(ContentsView* contents_view,
+                                         AppListItemList* item_list)
+    : contents_view_(contents_view), folder_image_(item_list) {
   SetTitle(l10n_util::GetStringUTF16(IDS_APP_LIST_ALL_APPS));
-  // TODO(mgiuca): Set the button's icon.
+  folder_image_.AddObserver(this);
 }
 
 AllAppsTileItemView::~AllAppsTileItemView() {
+  folder_image_.RemoveObserver(this);
+}
+
+void AllAppsTileItemView::UpdateIcon() {
+  folder_image_.UpdateIcon();
 }
 
 void AllAppsTileItemView::ButtonPressed(views::Button* sender,
@@ -25,4 +31,8 @@ void AllAppsTileItemView::ButtonPressed(views::Button* sender,
       contents_view_->GetPageIndexForState(AppListModel::STATE_APPS));
 }
 
+void AllAppsTileItemView::OnFolderImageUpdated() {
+  SetIcon(folder_image_.icon());
+}
+
 }  // namespace app_list