Add common page filtering logic for page load metrics.

chrome/common/page_load_metrics/page_tracker_predicate.cc

+// Copyright 2015 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/common/page_load_metrics/page_tracker_predicate.h"
+
+namespace page_load_metrics {
+
+PageTrackerPredicate::PageTrackerPredicate() {}
+PageTrackerPredicate::~PageTrackerPredicate() {}
+
+bool PageTrackerPredicate::ShouldTrackPage() {
+  // Ignore non-HTTP schemes (e.g. chrome://).
+  if (!IsHTTPOrHTTPSUrl())
+    return false;
+
+  // Ignore NTP loads.
+  if (IsNewTabPageUrl())
+    return false;
+
+  if (HasCommitted()) {
+    // Ignore Chrome error pages (e.g. No Internet connection).
+    if (IsChromeErrorPage())
+      return false;
+
+    // Ignore network error pages (e.g. 4xx, 5xx).
+    if (IsNetworkErrorPage())
+      return false;
+
+    // Ignore non-HTML documents (e.g. SVG, images).
+    if (!IsHTMLOrXHTMLPage())
+      return false;
+  }
+  return true;
+}
+
+}  // namespace page_load_metrics