Add SafeBrowsingNavigationObserver to listen to navigation events

chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.cc

+// 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.
+
+#include "chrome/browser/safe_browsing/safe_browsing_navigation_observer_manager.h"
+
+#include "base/memory/ptr_util.h"
+#include "base/time/time.h"
+#include "chrome/browser/chrome_notification_types.h"
+#include "chrome/browser/safe_browsing/safe_browsing_navigation_observer.h"
+#include "chrome/browser/sessions/session_tab_helper.h"
+#include "chrome/browser/tab_contents/retargeting_details.h"
+#include "content/public/browser/navigation_details.h"
+#include "content/public/browser/notification_service.h"
+#include "content/public/browser/notification_types.h"
+#include "content/public/browser/render_frame_host.h"
+#include "content/public/browser/render_process_host.h"
+#include "content/public/browser/web_contents.h"
+
+using content::WebContents;
+namespace safe_browsing {
+
+static const double kUserGestureTTLInSecond = 0.5;

[Nathan Parker, 2016/10/14 23:52:49]

Add a comment to explain what this does, or how it was chosen.

[Jialiu Lin, 2016/10/17 19:17:15]

Done.

+
+// static
+bool SafeBrowsingNavigationObserverManager::IsUserGestureExpired(
+    const base::Time& timestamp) {
+  double now = base::Time::Now().ToDoubleT();
+  double timestamp_in_double = timestamp.ToDoubleT();
+  return now > timestamp_in_double
+             ? now - timestamp_in_double > kUserGestureTTLInSecond

[Nathan Parker, 2016/10/14 23:52:49]

Should be safe to just

return now - timestamp_in_double > kUserGestureTTLInSecond

[Jialiu Lin, 2016/10/17 19:17:15]

ACK. 
I would like to return expired (true) if timestamp is in the future ( larger
than now, which suggests invalid).
but now - timestamp_in_double > kUserGestureTTLInSecond would return otherwise.

+             : true;
+}
+
+// static
+GURL SafeBrowsingNavigationObserverManager::ClearEmptyURLRef(const GURL& url) {
+  if (url.has_ref() && url.ref().empty()) {
+    url::Replacements<char> replacements;
+    replacements.ClearRef();
+    return url.ReplaceComponents(replacements);
+  }
+  return url;
+}
+
+SafeBrowsingNavigationObserverManager::SafeBrowsingNavigationObserverManager() {
+  registrar_.Add(this, chrome::NOTIFICATION_RETARGETING,
+                 content::NotificationService::AllSources());
+}
+
+void SafeBrowsingNavigationObserverManager::RecordNavigationEvent(
+    const GURL& nav_event_key,
+    NavigationEvent* nav_event) {
+  auto insertion_result = navigation_map_.insert(
+      std::make_pair(nav_event_key, std::vector<NavigationEvent>()));
+
+  insertion_result.first->second.push_back(std::move(*nav_event));

[Nathan Parker, 2016/10/14 23:52:49]

Does the std::move destroy the nav_event? If so, maybe add that to this
function's comments in the .h

[Jialiu Lin, 2016/10/17 19:17:15]

Done.

+}
+
+void SafeBrowsingNavigationObserverManager::RecordUserGestureForWebContents(
+    content::WebContents* web_contents,
+    const base::Time& timestamp) {
+  auto insertion_result =
+      user_gesture_map_.insert(std::make_pair(web_contents, timestamp));
+  if (!insertion_result.second)

[Nathan Parker, 2016/10/14 23:52:49]

nit: add comment, like // Update the timestamp if entry already exists.

(I find "thing.first.second," etc, challenging to follow since the types are non
obvious, so comments are useful)

[Jialiu Lin, 2016/10/17 19:17:15]

Agree. comment added. 

+    insertion_result.first->second = timestamp;
+}
+
+void SafeBrowsingNavigationObserverManager::OnUserGestureConsumed(
+    content::WebContents* web_contents,
+    const base::Time& timestamp) {
+  auto it = user_gesture_map_.find(web_contents);
+  if (it == user_gesture_map_.end())
+    return;
+  if (timestamp >= it->second)
+    user_gesture_map_.erase(web_contents);

[Nathan Parker, 2016/10/14 23:52:49]

Some comments here would help, since I'm not clear on why it's being erased.

Also, I think you can save another lookup by doing erase(it)

[Jialiu Lin, 2016/10/17 19:17:15]

Done.

+}
+
+void SafeBrowsingNavigationObserverManager::RecordHostToIpMapping(
+    const std::string& host,
+    const std::string& ip) {
+  auto insert_result = host_to_ip_map_.insert(
+      std::make_pair(host, std::vector<ResolvedIPAddress>()));
+  if (!insert_result.second) {
+    // host_to_ip_map already contains this key.
+    // If this IP is already in the vector, we update its timestamp.
+    for (auto& vector_entry : insert_result.first->second) {
+      if (vector_entry.ip == host) {
+        vector_entry.timestamp = base::Time::Now();
+        return;
+      }
+    }
+  }
+  // If this is a new IP of this host, and we added to the end of the vector.
+  insert_result.first->second.push_back(
+      ResolvedIPAddress(base::Time::Now(), ip));
+}
+
+void SafeBrowsingNavigationObserverManager::OnWebContentDestroyed(
+    content::WebContents* web_contents) {
+  user_gesture_map_.erase(web_contents);
+  // TODO (jialiul): Will add other clean up tasks shortly.
+}
+
+SafeBrowsingNavigationObserverManager::
+    ~SafeBrowsingNavigationObserverManager() {}
+
+void SafeBrowsingNavigationObserverManager::Observe(
+    int type,
+    const content::NotificationSource& source,
+    const content::NotificationDetails& details) {
+  if (type == chrome::NOTIFICATION_RETARGETING)
+    RecordRetargeting(details);
+}
+
+void SafeBrowsingNavigationObserverManager::RecordRetargeting(
+    const content::NotificationDetails& details) {
+  const RetargetingDetails* retargeting_detail =
+      content::Details<const RetargetingDetails>(details).ptr();
+  DCHECK(retargeting_detail);
+  content::WebContents* source_contents =
+      retargeting_detail->source_web_contents;
+  content::WebContents* target_contents =
+      retargeting_detail->target_web_contents;
+  DCHECK(source_contents);
+  DCHECK(target_contents);
+
+  content::RenderFrameHost* rfh = content::RenderFrameHost::FromID(
+      retargeting_detail->source_render_process_id,
+      retargeting_detail->source_render_frame_id);
+  const GURL& target_url =
+      SafeBrowsingNavigationObserverManager::ClearEmptyURLRef(

[Nathan Parker, 2016/10/14 23:52:49]

Add a comment as to why ClearEmptyURLRef() is this necessary.

[Jialiu Lin, 2016/10/17 19:17:15]

Done.

+          retargeting_detail->target_url);
+
+  navigation_map_.insert(
+      std::make_pair(target_url, std::vector<NavigationEvent>()));

[Nathan Parker, 2016/10/14 23:52:49]

If you save the iterator this returns, you can do the push_back() later w/o
re-searching the map.  Actually, this should probably be moved down there for
clarity.

[Jialiu Lin, 2016/10/17 19:17:15]

Thanks for catching these. 

+
+  NavigationEvent nav_event;
+  nav_event.source_url =

[Nathan Parker, 2016/10/14 23:52:49]

since source_url is already empty, you could do
if (rfh) {
  nav_event.source_url = ..
}

and skip the temporary GURL() creation.

[Jialiu Lin, 2016/10/17 19:17:15]

Done.

+      rfh ? SafeBrowsingNavigationObserverManager::ClearEmptyURLRef(
+                rfh->GetLastCommittedURL())
+          : GURL();
+  nav_event.source_tab_id = SessionTabHelper::IdForTab(source_contents);
+  nav_event.target_url = target_url;
+  nav_event.target_tab_id = SessionTabHelper::IdForTab(target_contents);
+  nav_event.frame_id = rfh ? rfh->GetFrameTreeNodeId() : -1;
+  nav_event.main_frame_url =
+      SafeBrowsingNavigationObserverManager::ClearEmptyURLRef(
+          source_contents->GetLastCommittedURL());
+  nav_event.timestamp = base::Time::Now();

[Nathan Parker, 2016/10/14 23:52:49]

This is already set in the nav_event ctor.  You could remove it from there.

[Jialiu Lin, 2016/10/17 19:17:15]

Yes, this is redundant. Fixed.

+  auto it = user_gesture_map_.find(source_contents);
+  if (it != user_gesture_map_.end() &&
+      !SafeBrowsingNavigationObserverManager::IsUserGestureExpired(
+          it->second)) {
+    nav_event.is_user_initiated = true;
+    OnUserGestureConsumed(it->first, it->second);
+  } else {
+    nav_event.is_user_initiated = false;
+  }
+
+  navigation_map_[target_url].push_back(std::move(nav_event));
+}
+
+}  // namespace safe_browsing