[Android WebView] Call shouldInterceptRequest on a background thread

android_webview/browser/aw_contents_io_thread_client.h

 // 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.
 
 #ifndef ANDROID_WEBVIEW_BROWSER_AW_CONTENTS_IO_THREAD_CLIENT_H_
 #define ANDROID_WEBVIEW_BROWSER_AW_CONTENTS_IO_THREAD_CLIENT_H_
 
 #include <string>
 
+#include "base/callback_forward.h"
 #include "base/memory/scoped_ptr.h"
 
 class GURL;
 
 namespace net {
 class HttpResponseHeaders;
 class URLRequest;
 }
 
 namespace android_webview {
@@ skipping 42 matching lines @@
   // An empty scoped_ptr is a valid return value.
   static scoped_ptr<AwContentsIoThreadClient> FromID(int render_process_id,
                                                      int render_frame_id);
 
   // Called on the IO thread when a subframe is created.
   static void SubFrameCreated(int render_process_id,
                               int parent_render_frame_id,
                               int child_render_frame_id);
 
   // This method is called on the IO thread only.
-  virtual scoped_ptr<AwWebResourceResponse> ShouldInterceptRequest(
-      const net::URLRequest* request) = 0;
+  typedef base::Callback<void(scoped_ptr<AwWebResourceResponse>)>
+      ShouldInterceptRequestResultCallback;
+  virtual void ShouldInterceptRequestAsync(
+      const net::URLRequest* request,
+      const ShouldInterceptRequestResultCallback callback) = 0;
 
   // Retrieve the AllowContentAccess setting value of this AwContents.
   // This method is called on the IO thread only.
   virtual bool ShouldBlockContentUrls() const = 0;
 
   // Retrieve the AllowFileAccess setting value of this AwContents.
   // This method is called on the IO thread only.
   virtual bool ShouldBlockFileUrls() const = 0;
 
   // Retrieve the BlockNetworkLoads setting value of this AwContents.
@@ skipping 25 matching lines @@
 
   // Called when a response from the server is received with status code >= 400.
   virtual void OnReceivedHttpError(
       const net::URLRequest* request,
       const net::HttpResponseHeaders* response_headers) = 0;
 };
 
 } // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_BROWSER_AW_CONTENTS_IO_THREAD_CLIENT_H_