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

chrome/browser/net/predictor_tab_helper.cc

+// Copyright (c) 2012 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/net/predictor_tab_helper.h"
+
+#include "chrome/browser/net/predictor.h"
+#include "chrome/browser/profiles/profile.h"
+#include "content/public/browser/browser_thread.h"
+#include "content/public/common/frame_navigate_params.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(chrome_browser_net::PredictorTabHelper);
+
+using content::BrowserThread;
+
+namespace {
+
+bool IsUserLinkNavigationRequest(content::PageTransition page_transition) {
+  bool is_link = (content::PageTransitionStripQualifier(page_transition) ==
+                  content::PAGE_TRANSITION_LINK);
+  bool is_forward_back = (page_transition &
+                          content::PAGE_TRANSITION_FORWARD_BACK) != 0;
+  // Tracking navigation session including client-side redirect
+  // is currently not supported.
+  bool is_client_redirect = (page_transition &
+                             content::PAGE_TRANSITION_CLIENT_REDIRECT) != 0;
+  return is_link && !is_forward_back && !is_client_redirect;
+}
+
+}  // namespace
+
+namespace chrome_browser_net {
+
+PredictorTabHelper::PredictorTabHelper(content::WebContents* web_contents)
+    : content::WebContentsObserver(web_contents) {
+}
+
+PredictorTabHelper::~PredictorTabHelper() {
+}
+
+void PredictorTabHelper::DidNavigateMainFrame(
+    const content::LoadCommittedDetails& details,
+    const content::FrameNavigateParams& params) {
+  if (!IsUserLinkNavigationRequest(params.transition) ||
+      !(params.url.SchemeIs("http") || params.url.SchemeIs("https")))
+    return;
+
+  Profile* profile = Profile::FromBrowserContext(
+      web_contents()->GetBrowserContext());
+  Predictor* predictor = profile->GetNetworkPredictor();
+  if (predictor) {
+    BrowserThread::PostTask(
+        BrowserThread::IO,
+        FROM_HERE,
+        base::Bind(&Predictor::RecordLinkNavigation,
+                   base::Unretained(predictor),
+                   params.url));
+  }
+}
+
+}  // namespace chrome_browser_net