Add UMA for first app list paint on Windows.

chrome/browser/ui/views/app_list/app_list_controller_win.cc

Index: chrome/browser/ui/views/app_list/app_list_controller_win.cc
diff --git a/chrome/browser/ui/views/app_list/app_list_controller_win.cc b/chrome/browser/ui/views/app_list/app_list_controller_win.cc
index a47ea339872b5b0c7dbc62285d63b9ce6e2d8cc9..8470790b30b1e0144d42f0c9102e407f8c7776f8 100644
--- a/chrome/browser/ui/views/app_list/app_list_controller_win.cc
+++ b/chrome/browser/ui/views/app_list/app_list_controller_win.cc
@@ -799,6 +799,8 @@ class AppListController : public AppListServiceImpl {
   void OnAppListActivationChanged(bool active);
 
   // AppListService overrides:
+  virtual void SetAppListNextPaintCallback(
+      const base::Closure& callback) OVERRIDE;
   virtual void HandleFirstRun() OVERRIDE;
   virtual void Init(Profile* initial_profile) OVERRIDE;
   virtual void CreateForProfile(Profile* requested_profile) OVERRIDE;
@@ -987,6 +989,11 @@ void AppListController::OnLoadProfileForWarmup(Profile* initial_profile) {
   shower_->WarmupForProfile(initial_profile);
 }
 
+void AppListController::SetAppListNextPaintCallback(
+    const base::Closure& callback) {
+  app_list::AppListView::SetAppListNextPaintCallback(callback);
+}
+
 void AppListController::HandleFirstRun() {
   PrefService* local_state = g_browser_process->local_state();
   // If the app list is already enabled during first run, then the user had