Add FrameNavigationEntry class.

content/browser/frame_host/frame_navigation_entry.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 "content/browser/frame_host/frame_navigation_entry.h"
+
+namespace content {
+
+FrameNavigationEntry::FrameNavigationEntry() {
+}
+
+FrameNavigationEntry::FrameNavigationEntry(SiteInstanceImpl* site_instance,
+                                           const GURL& url,
+                                           const Referrer& referrer)
+    : site_instance_(site_instance),
+      url_(url),
+      referrer_(referrer) {
+}
+
+FrameNavigationEntry::~FrameNavigationEntry() {
+}
+
+}  // namespace content