reintroduce InterceptDownloadResourceThrottle for some OMA DRM downloads

chrome/browser/android/download/download_controller.h

 // Copyright 2016 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.
 
 // This class pairs with DownloadController on Java side to forward requests
 // for GET downloads to the current DownloadListener. POST downloads are
 // handled on the native side.
 //
 // Both classes are Singleton classes. C++ object owns Java object.
 //
@@ skipping 26 matching lines @@
 
   static bool RegisterDownloadController(JNIEnv* env);
 
   // Called when DownloadController Java object is instantiated.
   void Init(JNIEnv* env, jobject obj);
 
   // DownloadControllerBase implementation.
   void AcquireFileAccessPermission(
       content::WebContents* web_contents,
       const AcquireFileAccessPermissionCallback& callback) override;
+  void CreateAndroidDownload(
+      const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
+      const DownloadInfo& info) override;
 
   // UMA histogram enum for download cancellation reasons. Keep this
   // in sync with MobileDownloadCancelReason in histograms.xml. This should be
   // append only.
   enum DownloadCancelReason {
     CANCEL_REASON_NOT_CANCELED = 0,
     CANCEL_REASON_ACTION_BUTTON,
     CANCEL_REASON_NOTIFICATION_DISMISSED,
     CANCEL_REASON_OVERWRITE_INFOBAR_DISMISSED,
     CANCEL_REASON_NO_STORAGE_PERMISSION,
@@ skipping 23 matching lines @@
 
   // DownloadItem::Observer interface.
   void OnDownloadUpdated(content::DownloadItem* item) override;
 
   // The download item contains dangerous file types.
   void OnDangerousDownload(content::DownloadItem *item);
 
   base::android::ScopedJavaLocalRef<jobject> GetContentViewCoreFromWebContents(
       content::WebContents* web_contents);
 
+  // Helper methods to start android download on UI thread.
+  void StartAndroidDownload(
+      const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
+      const DownloadInfo& info);
+  void StartAndroidDownloadInternal(
+      const content::ResourceRequestInfo::WebContentsGetter& wc_getter,
+      const DownloadInfo& info, bool allowed);
+
   // Creates Java object if it is not created already and returns it.
   JavaObject* GetJavaObject();
 
   JavaObject* java_object_;
 
   std::string default_file_name_;
 
   DISALLOW_COPY_AND_ASSIGN(DownloadController);
 };
 
 #endif  // CHROME_BROWSER_ANDROID_DOWNLOAD_DOWNLOAD_CONTROLLER_H_