Add metrics for calculating precision/recall of link navigation pre-connect triggers.

chrome/browser/net/predictor_tab_helper.h

+// Copyright 2013 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_NET_PREDICTOR_TAB_HELPER_H_
+#define CHROME_BROWSER_NET_PREDICTOR_TAB_HELPER_H_
+
+#include "content/public/browser/notification_observer.h"
+#include "content/public/browser/notification_registrar.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
+
+namespace chrome_browser_net {
+
+class PredictorTabHelper
+    : public content::NotificationObserver,
+      public content::WebContentsUserData<PredictorTabHelper> {
+ public:
+  virtual ~PredictorTabHelper();
+
+  // content::NotificationObserver implementation
+  virtual void Observe(int type,
+                       const content::NotificationSource& source,
+                       const content::NotificationDetails& details) OVERRIDE;
+
+ private:
+  explicit PredictorTabHelper(content::WebContents* web_contents);
+  friend class content::WebContentsUserData<PredictorTabHelper>;
+
+  void DidNavigation(const GURL& url, const GURL& original_url);
+
+  content::NotificationRegistrar registrar_;
+
+  content::WebContents* const web_contents_;
+
+  DISALLOW_COPY_AND_ASSIGN(PredictorTabHelper);
+};
+
+}  // namespace chrome_browser_net
+
+#endif  // CHROME_BROWSER_NET_PREDICTOR_TAB_HELPER_H_