Wire up download attribution enable finch experiment

chrome/browser/safe_browsing/safe_browsing_navigation_observer.h

Index: chrome/browser/safe_browsing/safe_browsing_navigation_observer.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_navigation_observer.h b/chrome/browser/safe_browsing/safe_browsing_navigation_observer.h
index 85321e69b593f7c6eefc15854803ed12bfee5b56..876dadd103fb9ab548da7e7d1d3265879ebc684b 100644
--- a/chrome/browser/safe_browsing/safe_browsing_navigation_observer.h
+++ b/chrome/browser/safe_browsing/safe_browsing_navigation_observer.h
@@ -64,7 +64,10 @@ struct ResolvedIPAddress {
 class SafeBrowsingNavigationObserver : public base::SupportsUserData::Data,
                                        public content::WebContentsObserver {
  public:
-  static void MaybeCreateForWebContents(content::WebContents* web_contents);
+  static void CreateForWebContents(
+      content::WebContents* web_contents,
+      const scoped_refptr<SafeBrowsingNavigationObserverManager>& manager);
+
   static SafeBrowsingNavigationObserver* FromWebContents(
       content::WebContents* web_contents);