Refactor the loading tracking logic in WebContentsImpl.

content/browser/frame_host/frame_tree_node.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 CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 #define CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "content/browser/frame_host/render_frame_host_impl.h"
 #include "content/browser/frame_host/render_frame_host_manager.h"
 #include "content/common/content_export.h"
 #include "content/common/frame_replication_state.h"
 #include "url/gurl.h"
 #include "url/origin.h"
 
 namespace content {
 
 class FrameTree;
 class Navigator;
 class RenderFrameHostImpl;
 
+// These values indicate the loading progress status.
+// The minimum progress vlaue matches what Blink's ProgressTracker has

[clamy, 2015/02/16 14:20:59]

nit: s/vlaue/value
Also I don't think that a line return is necessary here.

[Fabrice (no longer in Chrome), 2015/02/20 12:58:58]

Done.

+// traditionally used for a minimum progress value.
+const double kNotStartedLoadingProgress = 0.0;

[clamy, 2015/02/16 14:20:59]

So I've found an example of const values in the code at
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/fr...
. I think we should try to match that here.

[Fabrice (no longer in Chrome), 2015/02/20 12:58:58]

Done.

+const double kMinimumLoadingProgress = 0.1;
+const double kDoneLoadingProgress = 1.0;
+
 // When a page contains iframes, its renderer process maintains a tree structure
 // of those frames. We are mirroring this tree in the browser process. This
 // class represents a node in this tree and is a wrapper for all objects that
 // are frame-specific (as opposed to page-specific).
 class CONTENT_EXPORT FrameTreeNode {
  public:
 
   FrameTreeNode(FrameTree* frame_tree,
                 Navigator* navigator,
                 RenderFrameHostDelegate* render_frame_delegate,
@@ skipping 64 matching lines @@
     return replication_state_.origin.IsSameAs(node.replication_state_.origin);
   }
 
   const FrameReplicationState& current_replication_state() const {
     return replication_state_;
   }
 
   void set_is_loading(bool is_loading) {
     is_loading_ = is_loading;
   }
+
   bool is_loading() const {
     return is_loading_;
   }
 
+  void set_loading_progress(double loading_progress) {
+    loading_progress_ = loading_progress;
+  }
+
+  double get_loading_progress() const { return loading_progress_; }
+
   RenderFrameHostImpl* current_frame_host() const {
     return render_manager_.current_frame_host();
   }
 
   bool IsDescendantOf(FrameTreeNode* other) const;
 
  private:
   void set_parent(FrameTreeNode* parent) { parent_ = parent; }
 
   // The next available browser-global FrameTreeNode ID.
@@ skipping 35 matching lines @@
 
   // Boolean value indicating whether the frame is in the process of loading
   // a document or not. In cross-process transfer navigation the DidStartLoading
   // message is received from both existing RenderFrame and from the pending
   // RenderFrame. However, there will be only one DidStopLoading message sent by
   // the pending-which-becomes-current RenderFrame. Since both renderers belong
   // to the FrameTreeNode, it is better to ask it about the loading status than
   // RenderFrameHost or using a counter to balance the events out.
   bool is_loading_;
 
+  // Double value representing the frame's completion progress (from 0 to 1).
+  double loading_progress_;
+
   DISALLOW_COPY_AND_ASSIGN(FrameTreeNode);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_FRAME_HOST_FRAME_TREE_NODE_H_