Save image should download the original image when Data Saver is enabled.

content/public/browser/android/download_controller_android.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 CONTENT_PUBLIC_BROWSER_ANDROID_DOWNLOAD_CONTROLLER_ANDROID_H_
 #define CONTENT_PUBLIC_BROWSER_ANDROID_DOWNLOAD_CONTROLLER_ANDROID_H_
 
 #include "content/common/content_export.h"
 #include "content/public/common/context_menu_params.h"
 
@@ skipping 14 matching lines @@
                                  int request_id) = 0;
 
   // Should be called when a download is started. It can be either a GET
   // request with authentication or a POST request. Notifies the embedding
   // app about the download. Should be called on the UI thread.
   virtual void OnDownloadStarted(DownloadItem* download_item) = 0;
 
   // Called when a download is initiated by context menu.
   virtual void StartContextMenuDownload(
       const ContextMenuParams& params, WebContents* web_contents,
-      bool is_link) = 0;
+      bool is_link, const std::string& headers) = 0;

[Ted C, 2015/06/23 16:32:53]

I would call this extra_headers to be consistent (or rename the others to
headers -- whatever you prefer)

[megjablon, 2015/06/23 20:29:47]

Done.

 
   // Called when a dangerous download item is verified or rejected.
   virtual void DangerousDownloadValidated(
       WebContents* web_contents, int download_id, bool accept) = 0;
 
  protected:
   virtual ~DownloadControllerAndroid() {};
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_ANDROID_DOWNLOAD_CONTROLLER_ANDROID_H_