If a download is initiated by download attribute, don't use stream viewer

chrome/browser/android/intercept_download_resource_throttle.h

 // Copyright 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 CHROME_BROWSER_ANDROID_INTERCEPT_DOWNLOAD_RESOURCE_THROTTLE_H_
 #define CHROME_BROWSER_ANDROID_INTERCEPT_DOWNLOAD_RESOURCE_THROTTLE_H_
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "content/public/browser/resource_throttle.h"
 
 namespace net {
 class URLRequest;
 }
 
 namespace chrome {
 
 // InterceptDownloadResourceThrottle checks if a download request should be
 // handled by Chrome or passsed to the Android Download Manager.
 class InterceptDownloadResourceThrottle : public content::ResourceThrottle {
  public:
   static bool IsDownloadInterceptionEnabled();
 
   InterceptDownloadResourceThrottle(net::URLRequest* request,
                                     int render_process_id,
                                     int render_view_id,
-                                    int request_id);
+                                    int request_id,
+                                    bool must_download);
 
   // content::ResourceThrottle implementation:
   void WillProcessResponse(bool* defer) override;
   const char* GetNameForLogging() const override;
 
  private:
   ~InterceptDownloadResourceThrottle() override;
 
   void ProcessDownloadRequest();
   // Set to true when if we want chrome to handle the download.
   const net::URLRequest* request_;
   int render_process_id_;
   int render_view_id_;
   int request_id_;
+  bool must_download_;
 
   DISALLOW_COPY_AND_ASSIGN(InterceptDownloadResourceThrottle);
 };
 
 }  // namespace chrome
 
 #endif  // CHROME_BROWSER_ANDROID_INTERCEPT_DOWNLOAD_RESOURCE_THROTTLE_H_