Refactor the loading tracking logic in WebContentsImpl.

content/browser/frame_host/frame_tree_node.cc

 // 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.
 
 #include "content/browser/frame_host/frame_tree_node.h"
 
 #include <queue>
 
 #include "base/command_line.h"
 #include "base/stl_util.h"
@@ skipping 17 matching lines @@
     : frame_tree_(frame_tree),
       navigator_(navigator),
       render_manager_(this,
                       render_frame_delegate,
                       render_view_delegate,
                       render_widget_delegate,
                       manager_delegate),
       frame_tree_node_id_(next_frame_tree_node_id_++),
       parent_(NULL),
       replication_state_(name),
-      is_loading_(false) {
+      is_loading_(false),
+      loading_progress_(kNotStartedLoadingProgress) {
 }
 
 FrameTreeNode::~FrameTreeNode() {
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kEnableBrowserSideNavigation)) {
     navigator_->CancelNavigation(this);
   }
 }
 
 bool FrameTreeNode::IsMainFrame() const {
@@ skipping 60 matching lines @@
 
   for (FrameTreeNode* node = parent(); node; node = node->parent()) {
     if (node == other)
       return true;
   }
 
   return false;
 }
 
 }  // namespace content