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 ccf2b04eefe6eaaf5ea9c5f59308894a4ffc2203..6fdf7c37fb82b2b7c9bdc40c04f7efbc4c826706 100644
--- a/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
+++ b/chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h
@@ -70,6 +70,7 @@ class SafeBrowsingNavigationObserverManager
                                        const base::Time& timestamp);
   void OnUserGestureConsumed(content::WebContents* web_contents,
                              const base::Time& timestamp);
+  bool HasUserGesture(content::WebContents* web_contents);
   void RecordHostToIpMapping(const std::string& host, const std::string& ip);
 
   // Clean-ups need to be done when a WebContents gets destroyed.
@@ -85,12 +86,27 @@ 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 |tab_id|, 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,
+      int tab_id,
+      bool has_user_gesture,
+      int user_gesture_count_limit,
+      std::vector<ReferrerChainEntry>* out_referrer_chain);
+
  private:
   friend class base::RefCountedThreadSafe<
       SafeBrowsingNavigationObserverManager>;
@@ -168,6 +184,16 @@ 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