Wireup SafeBrowsingNavigationObserverManager to help PPAPI download attribution

chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h

Index: chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
diff --git a/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h b/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
index 9bfcfa1bb44a54f993475f9e472ace0c546b2ed0..87abb017473d0abf8e7aaaef3c96d58873ffceef 100644
--- a/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
+++ b/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
@@ -85,12 +85,26 @@ class SafeBrowsingNavigationObserverManager
   // |user_gesture_count_limit| number of user gestures. Then convert these
   // identified NavigationEvents into ReferrerChainEntrys and append them to
   // |out_referrer_chain|.
-  AttributionResult IdentifyReferrerChain(
+  AttributionResult IdentifyReferrerChainForDownload(
       const GURL& target_url,
       int target_tab_id,  // -1 if tab id is not valid
       int user_gesture_count_limit,
       std::vector<ReferrerChainEntry>* out_referrer_chain);
 
+  // Based on the |initiating_frame_url| and its associated |web_contents|,
+  // trace back the observed NavigationEvents in navigation_map_ to identify the
+  // sequence of navigations leading to this |initiating_frame_url|. If this
+  // initiating frame has a user gesture, we trace back with the coverage
+  // limited to |user_gesture_count_limit|-1 number of user gestures, otherwise
+  // we trace back |user_gesture_count_limit| number of user gestures. We then
+  // convert these identified NavigationEvents into ReferrerChainEntrys and
+  // append them to |out_referrer_chain|.
+  AttributionResult IdentifyReferrerChainForPPAPIDownload(
+      const GURL& initiating_frame_url,
+      content::WebContents* web_contents,
+      int user_gesture_count_limit,
+      std::vector<ReferrerChainEntry>* out_referrer_chain);
+
  private:
   friend class base::RefCountedThreadSafe<
       SafeBrowsingNavigationObserverManager>;
@@ -162,6 +176,16 @@ class SafeBrowsingNavigationObserverManager
                           NavigationEvent* nav_event,
                           ReferrerChainEntry::URLType type);
 
+  // Helper function to get the remaining referrer chain when we've already
+  // traced back |current_user_gesture_count| number of user gestures.
+  // This function modifies the |out_referrer_chain| and |out_result|.
+  void GetRemainingReferrerChain(
+    NavigationEvent* last_nav_event_traced,
+    int current_user_gesture_count,
+    int user_gesture_count_limit,
+    std::vector<ReferrerChainEntry>* out_referrer_chain,
+    AttributionResult* out_result);
+
   // navigation_map_ keeps track of all the observed navigations. This map is
   // keyed on the resolved request url. In other words, in case of server
   // redirects, its key is the last server redirect url, otherwise, it is the