Wire up download attribution enable finch experiment

chrome/browser/safe_browsing/safe_browsing_service.h

Index: chrome/browser/safe_browsing/safe_browsing_service.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_service.h b/chrome/browser/safe_browsing/safe_browsing_service.h
index 27e15b03e9de51ac031f5fda6557acc9ee0be8dc..2e1c5f833a65789134dba2a39265f41c11515543 100644
--- a/chrome/browser/safe_browsing/safe_browsing_service.h
+++ b/chrome/browser/safe_browsing/safe_browsing_service.h
@@ -49,6 +49,7 @@ class DownloadProtectionService;
 struct ResourceRequestInfo;
 struct SafeBrowsingProtocolConfig;
 class SafeBrowsingDatabaseManager;
+class SafeBrowsingNavigationObserverManager;
 class SafeBrowsingPingManager;
 class SafeBrowsingProtocolManager;
 class SafeBrowsingProtocolManagerDelegate;
@@ -129,6 +130,9 @@ class SafeBrowsingService : public base::RefCountedThreadSafe<
   // the experiment settings.
   const scoped_refptr<SafeBrowsingDatabaseManager>& database_manager() const;
 
+  const scoped_refptr<SafeBrowsingNavigationObserverManager>&

[Nathan Parker, 2016/12/20 01:01:33]

I think the scoped_refptrs are better to return by copy:

scoped_refptr<SafeBrowsingNavigationObserverManager> nav_obs_mgr();

That way you can return null and have it generate a temporary.  We ran into
trouble with returning a ref with the DB manager, and I'm thinking we should
switch them all at some point.

[Jialiu Lin, 2016/12/20 02:07:51]

I see. let's only change SafeBrowsingNavigationObserverManager for now, and
clean up other scope_refptr later.

+  navigation_observer_manager() const;
+
   SafeBrowsingProtocolManager* protocol_manager() const;
 
   SafeBrowsingPingManager* ping_manager() const;
@@ -291,6 +295,10 @@ class SafeBrowsingService : public base::RefCountedThreadSafe<
   // both UI and IO thread.
   scoped_refptr<SafeBrowsingDatabaseManager> database_manager_;
 
+  // The navigation observer manager handles download attribution.
+  scoped_refptr<SafeBrowsingNavigationObserverManager>
+  navigation_observer_manager_;
+
   DISALLOW_COPY_AND_ASSIGN(SafeBrowsingService);
 };