Refactor the loading tracking logic in WebContentsImpl.

content/browser/frame_host/render_frame_host_impl.h

Index: content/browser/frame_host/render_frame_host_impl.h
diff --git a/content/browser/frame_host/render_frame_host_impl.h b/content/browser/frame_host/render_frame_host_impl.h
index ca442d27367f9a9f528b4d49454b85457810d156..601b989174cd1e2464f2ab065f452acc373579f3 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -94,6 +94,15 @@ class CONTENT_EXPORT RenderFrameHostImpl
     : public RenderFrameHost,
       public BrowserAccessibilityDelegate {
  public:
+  // These values indicate the loading progress status. The minimum progress
+  // value matches what Blink's ProgressTracker has traditionally used for a
+  // minimum progress value.
+  // TODO(fdegans): Move these values to the implementation when the relevant
+  // IPCs are moved from WebContentsImpl to RFHI.
+  static const double kLoadingProgressNotStarted;
+  static const double kLoadingProgressMinimum;
+  static const double kLoadingProgressDone;
+
   // Keeps track of the state of the RenderFrameHostImpl, particularly with
   // respect to swap out.
   enum RenderFrameHostImplState {
@@ -203,6 +212,16 @@ class CONTENT_EXPORT RenderFrameHostImpl
   RenderFrameHostDelegate* delegate() { return delegate_; }
   FrameTreeNode* frame_tree_node() { return frame_tree_node_; }
 
+  void set_is_loading(bool is_loading) {

[Charlie Reis, 2015/03/03 06:32:22]

Please document these, since it's unclear whether other callers in content
should use these or the ones in FrameTreeNode.  We should make it clear that
FrameTreeNode::IsLoading is the place to ask, and that these are just inputs to
it.

[Fabrice (no longer in Chrome), 2015/03/03 13:12:17]

Done.
I clarified the loading progress too.

+    is_loading_ = is_loading;
+  }
+  bool is_loading() const { return is_loading_; }
+
+  void set_loading_progress(double loading_progress) {
+    loading_progress_ = loading_progress;
+  }
+  double loading_progress() const { return loading_progress_; }
+
   // This returns the RenderFrameHost's owned RenderWidgetHost if it has one,
   // or else it returns nullptr.
   // If the RenderFrameHost is the page's main frame, this returns instead a
@@ -664,6 +683,13 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // PlzNavigate: all navigations require a beforeUnload ACK.
   bool unload_ack_is_for_navigation_;
 
+  // Indicates whether this RenderFrameHost is in the process of loading a
+  // document or not.
+  bool is_loading_;
+
+  // Used to represent this RenderFrameHost loading progress (from 0 to 1).
+  double loading_progress_;
+
   // Used to swap out or shut down this RFH when the unload event is taking too
   // long to execute, depending on the number of active frames in the
   // SiteInstance.