Notify launcher page with onTransitionChanged event

chrome/common/extensions/api/launcher_page_private.idl

Index: chrome/common/extensions/api/launcher_page_private.idl
diff --git a/chrome/common/extensions/api/launcher_page_private.idl b/chrome/common/extensions/api/launcher_page_private.idl
new file mode 100644
index 0000000000000000000000000000000000000000..a5e6d30dd36008461e545a1c25a211d40aef4787
--- /dev/null
+++ b/chrome/common/extensions/api/launcher_page_private.idl
@@ -0,0 +1,12 @@
+// 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.
+
+// The <code>chrome.launcherPagePrivate</code> API provides launcher pages in
+// the App Launcher with the capabilities and events they need.
+namespace launcherPagePrivate {
+  interface Events {
+    static void onPageExpand();
+    static void onPageCollapse();
+  };
+};