We have a problem in the process on destroying WebContentsImpl because

android_webview/native/aw_settings.h

 // Copyright (c) 2013 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_NATIVE_AW_SETTINGS_H_
 #define ANDROID_WEBVIEW_NATIVE_AW_SETTINGS_H_
 
 #include <jni.h>
 
 #include "base/android/jni_weak_ref.h"
@@ skipping 28 matching lines @@
 
   void PopulateWebPreferences(WebPreferences* web_prefs);
 
  private:
   AwRenderViewHostExt* GetAwRenderViewHostExt();
   void UpdateEverything();
 
   // WebContentsObserver overrides:
   virtual void RenderViewCreated(
       content::RenderViewHost* render_view_host) OVERRIDE;
-  virtual void WebContentsDestroyed(
-      content::WebContents* web_contents) OVERRIDE;
+  virtual void WebContentsDestroyed() OVERRIDE;
 
   bool accelerated_2d_canvas_disabled_by_switch_;
 
   bool renderer_prefs_initialized_;
 
   JavaObjectWeakGlobalRef aw_settings_;
 };
 
 bool RegisterAwSettings(JNIEnv* env);
 
 }  // namespace android_webview
 
 #endif  // ANDROID_WEBVIEW_NATIVE_AW_SETTINGS_H_