Add SafeBrowsingNavigationObserver to listen to navigation events

chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_NAVIGATION_OBSERVER_MANAGER_H_
+#define CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_NAVIGATION_OBSERVER_MANAGER_H_
+
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "url/gurl.h"
+
+namespace content {
+class NavigationHandle;
+struct ResourceRedirectDetails;
+}
+
+namespace safe_browsing {
+
+class SafeBrowsingNavigationObserver;
+struct NavigationEvent;
+
+// Manager class for SafeBrowsingNavigationObserver, which in charge of cleaning
+// up stale navigation events, and identifing landing page/landing referrer for
+// a specific download.
+// TODO(jialiul): For now, SafeBrowsingNavigationObserverManager also listens to
+// NOTIFICATION_RETARGETING as a way to detect cross frame/tab navigation.
+// Remove base class content::NotificationObserver when
+// WebContentsObserver::DidOpenRequestedURL() covers all retargeting cases.
+class SafeBrowsingNavigationObserverManager
+    : public content::NotificationObserver,
+      public base::RefCountedThreadSafe<SafeBrowsingNavigationObserverManager> {
+ public:
+  struct GurlHash {
+    std::size_t operator()(const GURL& url) const {
+      return std::hash<std::string>()(url.spec());
+    }
+  };
+  typedef std::unordered_map<GURL, std::vector<NavigationEvent>, GurlHash>
+      NavigationMap;
+
+  // Helper function to check if user gesture is older than
+  // kUserGestureTTLInSecond;
+  static bool IsUserGestureExpired(const base::Time& timestamp);
+  // Helper function to strip ref fragment from a URL.
+  static GURL ClearURLRef(const GURL& url);
+
+  SafeBrowsingNavigationObserverManager();
+  void RecordNavigationEvent(const GURL& nav_event_key,
+                             NavigationEvent* nav_event);
+  void RecordUserGestureForWebContents(content::WebContents* web_contents,
+                                       const base::Time& timestamp);
+  void OnUserGestureConsumed(content::WebContents* web_contents,
+                             const base::Time& timestamp);
+  // Clean-ups need to be done when a WebContents gets destroyed.
+  void OnWebContentDestroyed(content::WebContents* web_contents);
+
+  // TODO(jialiul): more functions are coming for managing navigation_map_.
+
+ private:
+  friend class base::RefCountedThreadSafe<
+      SafeBrowsingNavigationObserverManager>;
+  friend class TestNavigationObserverManager;
+  friend class SBNavigationObserverBrowserTest;
+  friend class SBNavigationObserverTest;
+
+  typedef std::unordered_map<content::WebContents*, base::Time> UserGestureMap;
+
+  ~SafeBrowsingNavigationObserverManager() override;
+
+  // content::NotificationObserver:
+  void Observe(int type,
+               const content::NotificationSource& source,
+               const content::NotificationDetails& details) override;
+
+  void RecordRetargeting(const content::NotificationDetails& details);
+
+  NavigationMap* navigation_map() { return &navigation_map_; }
+
+  // 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
+  // original target url. Since the same url can be requested multiple times
+  // across different tabs and frames, the value of this map is a vector of
+  // NavigationEvent ordered by navigation finish time. Entries in
+  // navigation_map_ will be removed if they are older than 2 minutes since
+  // their corresponding navigations finish.

[Charlie Reis, 2016/09/28 21:08:13]

Please make this last sentence a TODO, since it's not implemented yet.

[Jialiu Lin, 2016/09/28 21:39:14]

Done.

+  NavigationMap navigation_map_;
+
+  // user_gesture_map_ keeps track of the timestamp of last user gesture in
+  // in each WebContents. We assume for majority of cases, a navigation
+  // shortly after a user gesture indicate this navigation is user initiated.
+  UserGestureMap user_gesture_map_;
+
+  content::NotificationRegistrar registrar_;
+  DISALLOW_COPY_AND_ASSIGN(SafeBrowsingNavigationObserverManager);
+};
+}  // namespace safe_browsing
+
+#endif  // CHROME_BROWSER_SAFE_BROWSING_SAFE_BROWSING_NAVIGATION_OBSERVER_MANAGER_H_