Support restricting browsing data removal for downloads by origin.

content/public/browser/browser_context.h

Index: content/public/browser/browser_context.h
diff --git a/content/public/browser/browser_context.h b/content/public/browser/browser_context.h
index c15afefc81a7f91e864ffd94164d41881011c2c6..1c174291dc7210b1085d383db5d1414721249f06 100644
--- a/content/public/browser/browser_context.h
+++ b/content/public/browser/browser_context.h
@@ -120,6 +120,9 @@ class CONTENT_EXPORT BrowserContext : public base::SupportsUserData {
   // across the next restart.
   static void SaveSessionState(BrowserContext* browser_context);
 
+  static void SetDownloadManagerForTesting(BrowserContext* browser_context,
+                                           DownloadManager* download_manager);
+
   ~BrowserContext() override;
 
   // Creates a delegate to initialize a HostZoomMap and persist its information.