Flip --enable-apps-show-on-first-paint flag.

apps/app_window.cc

Index: apps/app_window.cc
diff --git a/apps/app_window.cc b/apps/app_window.cc
index 6412b1041ba6fabfa67aacdc51131a653731a2e6..ece3bcbbf53ae5ef7041929ed00a5c7540e061ec 100644
--- a/apps/app_window.cc
+++ b/apps/app_window.cc
@@ -238,6 +238,7 @@ AppWindow::AppWindow(BrowserContext* context,
       fullscreen_types_(FULLSCREEN_TYPE_NONE),
       show_on_first_paint_(false),
       first_paint_complete_(false),
+      has_been_shown_(false),
       is_hidden_(false),
       cached_always_on_top_(false) {
   extensions::ExtensionsBrowserClient* client =
@@ -253,8 +254,8 @@ void AppWindow::Init(const GURL& url,
   app_window_contents_.reset(app_window_contents);
   app_window_contents_->Initialize(browser_context(), url);
   WebContents* web_contents = app_window_contents_->GetWebContents();
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableAppsShowOnFirstPaint)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAppsShowOnFirstPaint)) {
     content::WebContentsObserver::Observe(web_contents);
   }
   delegate_->InitWebContents(web_contents);
@@ -326,8 +327,8 @@ void AppWindow::Init(const GURL& url,
 
   app_window_contents_->LoadContents(new_params.creator_process_id);
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableAppsShowOnFirstPaint)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAppsShowOnFirstPaint)) {
     // We want to show the window only when the content has been painted. For
     // that to happen, we need to define a size for the content, otherwise the
     // layout will happen in a 0x0 area.
@@ -679,8 +680,8 @@ void AppWindow::SetContentSizeConstraints(const gfx::Size& min_size,
 void AppWindow::Show(ShowType show_type) {
   is_hidden_ = false;
 
-  if (CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kEnableAppsShowOnFirstPaint)) {
+  if (!CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableAppsShowOnFirstPaint)) {
     show_on_first_paint_ = true;
 
     if (!first_paint_complete_) {
@@ -698,6 +699,11 @@ void AppWindow::Show(ShowType show_type) {
       break;
   }
   AppWindowRegistry::Get(browser_context_)->AppWindowShown(this);
+
+  if (!has_been_shown_) {
+    has_been_shown_ = true;
+    app_window_contents_->NativeWindowFirstShown();
+  }
 }
 
 void AppWindow::Hide() {