Enable download page action for error page

chrome/browser/android/offline_pages/offline_page_bridge.h

 // 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.
 
 #ifndef CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_BRIDGE_H_
 #define CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_BRIDGE_H_
 
 #include <stdint.h>
 
 #include "base/android/jni_android.h"
@@ skipping 86 matching lines @@
                      const base::android::JavaParamRef<jstring>& url,
                      const base::android::JavaParamRef<jstring>& j_namespace,
                      const base::android::JavaParamRef<jstring>& j_client_id,
                      jboolean user_requested);
 
   jboolean IsShowingOfflinePreview(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& j_web_contents);
 
+  jboolean IsShowingDownloadButtonInErrorPage(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobject>& j_web_contents);
+
   base::android::ScopedJavaLocalRef<jstring> GetOfflinePageHeaderForReload(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& j_web_contents);
 
   void GetRequestsInQueue(
       JNIEnv* env,
       const base::android::JavaParamRef<jobject>& obj,
       const base::android::JavaParamRef<jobject>& j_callback_obj);
 
@@ skipping 21 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(OfflinePageBridge);
 };
 
 bool RegisterOfflinePageBridge(JNIEnv* env);
 
 }  // namespace android
 }  // namespace offline_pages
 
 #endif  // CHROME_BROWSER_ANDROID_OFFLINE_PAGES_OFFLINE_PAGE_BRIDGE_H_