Add a new field "source" in launchData of chrome.app.runtime.onLaunched() to trace launch source.

extensions/common/api/app_runtime.idl

 // Copyright 2014 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.
 
 // Use the <code>chrome.app.runtime</code> API to manage the app lifecycle.
 // The app runtime manages app installation, controls the event page, and can
 // shut down the app at anytime.
 namespace app.runtime {
 
   [inline_doc] dictionary LaunchItem {
     // FileEntry for the file.
     [instanceOf=FileEntry] object entry;
 
     // The MIME type of the file.
     DOMString type;
   };
 
+  // Enumeration of app launch sources.
+  enum LaunchSource {
+    app_launcher,
+    new_tab_page,
+    restart,
+    reload,
+    file_handler,
+    url_handler,
+
+    // App-specific

[benwells, 2014/10/21 03:51:58]

Lets try and make these non-app specific. How about just:
system_tray,
about_page,
keyboard
?

[cylee1, 2014/10/21 13:41:17]

Done.

+    gethelp_system_tray,
+    gethelp_about_page,
+    gethelp_keyboard
+  };
+
   // Optional data for the launch. Either <code>items</code>, or
   // the pair (<code>url, referrerUrl</code>) can be present for any given
   // launch.
   [inline_doc] dictionary LaunchData {
     // The ID of the file or URL handler that the app is being invoked with.
     // Handler IDs are the top-level keys in the <code>file_handlers</code>
     // and/or <code>url_handlers</code> dictionaries in the manifest.
     DOMString? id;
 
     // The file entries for the <code>onLaunched</code> event triggered by a
     // matching file handler in the <code>file_handlers</code> manifest key.
     LaunchItem[]? items;
 
     // The URL for the <code>onLaunched</code> event triggered by a matching
     // URL handler in the <code>url_handlers</code> manifest key.
     DOMString? url;
 
     // The referrer URL for the <code>onLaunched</code> event triggered by a
     // matching URL handler in the <code>url_handlers</code> manifest key.
     DOMString? referrerUrl;
 
     // Whether the app is being launched in a <a
     // href="https://support.google.com/chromebook/answer/3134673">Chrome OS
     // kiosk session</a>.
     boolean? isKioskSession;
+
+    // Where the app is launched from.
+    LaunchSource? source;
   };
 
   // This object specifies details and operations to perform on the embedding
   // request. The app to be embedded can make a decision on whether or not to
   // allow the embedding and what to embed based on the embedder making the
   // request.
   dictionary EmbedRequest {
     DOMString embedderId;
 
     // Optional developer specified data that the app to be embedded can use
@@ skipping 15 matching lines @@
     static void onEmbedRequested(EmbedRequest request);
 
     // Fired when an app is launched from the launcher.
     static void onLaunched(optional LaunchData launchData);
 
     // Fired at Chrome startup to apps that were running when Chrome last shut
     // down.
     static void onRestarted();
   };
 };