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 71afa041fd9bba08b81c2c7aceed1b056e0f49ed..94207c5a43e1fcfc19f129683b863f056cac7ed0 100644
--- a/content/browser/frame_host/render_frame_host_impl.h
+++ b/content/browser/frame_host/render_frame_host_impl.h
@@ -94,6 +94,13 @@ 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.
+  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 +210,16 @@ class CONTENT_EXPORT RenderFrameHostImpl
   RenderFrameHostDelegate* delegate() { return delegate_; }
   FrameTreeNode* frame_tree_node() { return frame_tree_node_; }
 
+  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 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
@@ -663,6 +680,13 @@ class CONTENT_EXPORT RenderFrameHostImpl
   // PlzNavigate: all navigations require a beforeUnload ACK.
   bool unload_ack_is_for_navigation_;
 
+  // Boolean value indicating whether this RFH in the process of loading a
+  // document or not.
+  bool is_loading_;
+
+  // Double value representing this RFH's 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.