Use FrameTreeNode ID as frameId in extension APIs

chrome/test/data/extensions/api_test/webnavigation/crossProcessIframe/frame.js

Index: chrome/test/data/extensions/api_test/webnavigation/crossProcessIframe/frame.js
diff --git a/chrome/test/data/extensions/api_test/webnavigation/crossProcessIframe/frame.js b/chrome/test/data/extensions/api_test/webnavigation/crossProcessIframe/frame.js
new file mode 100644
index 0000000000000000000000000000000000000000..46e3f80adb7058c8aa777bf7e2b5a05e0afe3aa8
--- /dev/null
+++ b/chrome/test/data/extensions/api_test/webnavigation/crossProcessIframe/frame.js
@@ -0,0 +1,18 @@
+// Copyright 2015 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.
+
+onload = function() {
+  setTimeout(function() {
+    if (location.hostname === 'a.com') {
+      // Notify the parent frame, so they can navigate us.
+      parent.postMessage('a.com: go to b.com', location.ancestorOrigins[0]);
+    } else if (location.hostname === 'b.com') {
+      // Trigger a navigation to a site in another process.
+      location.hostname = 'c.com';
+    } else {
+      console.assert(location.hostname === 'c.com');
+      // Done.
+    }
+  }, 0);
+};