Use a resource throttle to implement shouldOverrideUrlLoading.

content/public/android/java/src/org/chromium/content_public/browser/WebContentsObserver.java

 // Copyright 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.
 
 package org.chromium.content_public.browser;
 
 import java.lang.ref.WeakReference;
 
 /**
  * This class receives callbacks that act as hooks for various a native web contents events related
@@ skipping 30 matching lines @@
      */
     public void didStopLoading(String url) {}
 
     /**
      * Called when an error occurs while loading a page and/or the page fails to load.
      * @param errorCode Error code for the occurring error.
      * @param description The description for the error.
      * @param failingUrl The url that was loading when the error occurred.
      */
     public void didFailLoad(boolean isProvisionalLoad, boolean isMainFrame, int errorCode,
-            String description, String failingUrl) {}
+            String description, String failingUrl, boolean wasIgnoredByHandler) {}
 
     /**
      * Called when the main frame of the page has committed.
      * @param url The validated url for the page.
      * @param baseUrl The validated base url for the page.
      * @param isNavigationToDifferentPage Whether the main frame navigated to a different page.
      * @param isFragmentNavigation Whether the main frame navigation did not cause changes to the
      *                             document (for example scrolling to a named anchor or PopState).
      * @param statusCode The HTTP status code of the navigation.
      */
@@ skipping 91 matching lines @@
     public void destroy() {
         if (mWebContents == null) return;
         final WebContents webContents = mWebContents.get();
         mWebContents = null;
         if (webContents == null) return;
         webContents.removeObserver(this);
     }
 
     protected WebContentsObserver() {}
 }