Implementation of the "Redirect URLs to Packaged Apps" feature.

chrome/renderer/resources/extensions/app_runtime_custom_bindings.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.
 
 // Custom binding for the chrome.app.runtime API.
 
 var binding = require('binding').Binding.create('app.runtime');
 
 var chromeHidden = requireNative('chrome_hidden').GetChromeHidden();
 var chrome = requireNative('chrome').GetChrome();
@@ skipping 34 matching lines @@
       });
     })(fe, fs);
   }
   dispatchIfNoPendingCallbacks();
 });
 
 chromeHidden.Event.registerArgumentMassager('app.runtime.onLaunched',
     function(args, dispatch) {
   var launchData = args[0];
 
-  if (launchData && typeof launchData.id !== 'undefined') {
-    // new-style dispatch.
+  if (!launchData) {
+    dispatch([]);
+    return;
+  }
+
+  if (launchData.items) {
+    // An onLaunched corresponding to file_handlers in the app's manifest.
+    // NOTE: Using the new-style dispatch.
     var items = []
     var numItems = launchData.items.length;
     var itemLoaded = function(err, item) {
       if (err) {
         console.error('Error getting fileEntry, code: ' + err.code);
       } else {
         items.push(item);
       }
       if (--numItems === 0) {
         if (items.length === 0) {
           dispatch([]);
         } else {
           var data = { id: launchData.id, items: items };
           dispatch([data]);
         }
       }
     };
     forEach(launchData.items, function(i, item) {
       var fs = GetIsolatedFileSystem(item.fileSystemId);
       fs.root.getFile(item.baseName, {}, function(fileEntry) {
         itemLoaded(null, { entry: fileEntry, type: item.mimeType });
       }, function(fileError) {
         itemLoaded(fileError);
       });
     });
-  } else if (launchData) {
+  } else {
+    // Default case. This currently covers an onLaunched corresponding to
+    // url_handlers in the app's manifest.
     dispatch([launchData]);
-  } else {
-    dispatch([]);
   }
 });
 
 exports.binding = binding.generate();