[Offline Pages] Add an observer for requests in the CCT namespace.

chrome/browser/android/app_hooks.h

 // Copyright 2017 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 CHROME_BROWSER_ANDROID_APP_HOOKS_H_
 #define CHROME_BROWSER_ANDROID_APP_HOOKS_H_
 
 #include <jni.h>
+#include "base/android/scoped_java_ref.h"
 #include "base/macros.h"
 
 namespace chrome {
 namespace android {
 
 class AppHooks {
  public:
   static bool ShouldDetectVideoFullscreen();
+  static base::android::ScopedJavaLocalRef<jobject>
+  GetOfflinePagesCCTRequestDoneCallback();
 
  private:
   AppHooks();
   ~AppHooks();
 
   DISALLOW_COPY_AND_ASSIGN(AppHooks);
 };
 
 }  // namespace android
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_APP_HOOKS_H_