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

chrome/test/data/extensions/platform_apps/prevent_leave_fullscreen/main.js

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 chrome.app.runtime.onLaunched.addListener(function() {
   chrome.app.window.create('main.html', {}, function(win) {
-    // The following key events handler will prevent the default behavior for
-    // the ESC key, thus will prevent the ESC key to leave fullscreen.
-    win.contentWindow.document.addEventListener('keydown', function(e) {
-      e.preventDefault();
-    });
-    win.contentWindow.document.addEventListener('keyup', function(e) {
-      e.preventDefault();
-    });
-
-    chrome.test.sendMessage('Launched', function(reply) {
-      var doc = win.contentWindow.document;
-      doc.addEventListener('keydown', function(e) {
-        if (e.keyCode != 90) // 'z'
-          return;
-        chrome.test.sendMessage('KeyReceived');
+    win.onWindowFirstShown.addListener(function() {
+      // The following key events handler will prevent the default behavior for
+      // the ESC key, thus will prevent the ESC key to leave fullscreen.
+      win.contentWindow.document.addEventListener('keydown', function(e) {
+        e.preventDefault();
+      });
+      win.contentWindow.document.addEventListener('keyup', function(e) {
+        e.preventDefault();
       });
 
-      switch (reply) {
-        case 'window':
-          doc.addEventListener('keydown', function(e) {
-            if (e.keyCode != 66) // 'b'
-              return;
-            doc.removeEventListener('keydown', arguments.callee);
-            // We do one trip to the event loop to increase the chances that
-            // fullscreen could have been left before the message is received.
-            setTimeout(function() {
-              chrome.test.sendMessage('B_KEY_RECEIVED');
-            });
-          });
-          win.fullscreen();
-          break;
+      chrome.test.sendMessage('Launched', function(reply) {
+        var doc = win.contentWindow.document;
+        doc.addEventListener('keydown', function(e) {
+          if (e.keyCode != 90) // 'z'
+            return;
+          chrome.test.sendMessage('KeyReceived');
+        });
 
-        case 'dom':
-          doc.addEventListener('keydown', function() {
-            doc.removeEventListener('keydown', arguments.callee);
-
+        switch (reply) {
+          case 'window':
             doc.addEventListener('keydown', function(e) {
               if (e.keyCode != 66) // 'b'
                 return;
               doc.removeEventListener('keydown', arguments.callee);
               // We do one trip to the event loop to increase the chances that
               // fullscreen could have been left before the message is received.
               setTimeout(function() {
                 chrome.test.sendMessage('B_KEY_RECEIVED');
               });
             });
+            win.fullscreen();
+            break;
 
-            doc.body.webkitRequestFullscreen();
-          });
-          break;
-      }
+          case 'dom':
+            doc.addEventListener('keydown', function() {
+              doc.removeEventListener('keydown', arguments.callee);
+
+              doc.addEventListener('keydown', function(e) {
+                if (e.keyCode != 66) // 'b'
+                  return;
+                doc.removeEventListener('keydown', arguments.callee);
+                // We do one trip to the event loop to increase the chances that
+                // fullscreen could have been left before the message is
+                // received.
+                setTimeout(function() {
+                  chrome.test.sendMessage('B_KEY_RECEIVED');
+                });
+              });
+
+              doc.body.webkitRequestFullscreen();
+            });
+            break;
+        }
+      });
     });
   });
 });