Update app runtime custom bindings to handle no WebIntents launch data.

chrome/test/data/extensions/api_test/webintent_handler/background.js

-// Copyright (c) 2012 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.
-
-/*
-This extension is a platform app that provides a Web Intent handler; it accepts
-incoming requests and invokes chrome.test.succeed() immediately.
-*/
-
-function launchedListener(launchData) {
-  chrome.test.assertFalse(!launchData, "No launchData");
-  chrome.test.assertFalse(!launchData.intent, "No launchData.intent");
-  chrome.test.assertEq(launchData.intent.action,
-      "http://webintents.org/view");
-  chrome.test.assertEq(launchData.intent.type,
-      "chrome-extension://fileentry");
-  chrome.test.assertFalse(!launchData.intent.data,
-      "No launchData.intent.data");
-
-  launchData.intent.data.file(function(file) {
-    var reader = new FileReader();
-    reader.onloadend = function(e) {
-      chrome.test.assertEq("hello, world!", reader.result);
-      chrome.test.succeed();
-    };
-    reader.onerror = function(e) {
-      chrome.test.fail("Error reading file contents.");
-    };
-    reader.readAsText(file);
-  });
-}
-
-chrome.app.runtime.onLaunched.addListener(launchedListener);