Refactor the loading tracking logic in WebContentsImpl.

content/browser/frame_host/render_frame_host_impl.cc

Index: content/browser/frame_host/render_frame_host_impl.cc
diff --git a/content/browser/frame_host/render_frame_host_impl.cc b/content/browser/frame_host/render_frame_host_impl.cc
index 38f4192c62ab9c49290126814c0db5313c88ade3..362b36f5490b7a35ea9c1cad85d80b31cbb433ac 100644
--- a/content/browser/frame_host/render_frame_host_impl.cc
+++ b/content/browser/frame_host/render_frame_host_impl.cc
@@ -104,6 +104,10 @@ base::i18n::TextDirection WebTextDirectionToChromeTextDirection(
 
 }  // namespace
 
+const double RenderFrameHostImpl::kLoadingProgressNotStarted = 0.0;
+const double RenderFrameHostImpl::kLoadingProgressMinimum = 0.1;
+const double RenderFrameHostImpl::kLoadingProgressDone = 1.0;
+
 // static
 bool RenderFrameHostImpl::IsRFHStateActive(RenderFrameHostImplState rfh_state) {
   return rfh_state == STATE_DEFAULT;
@@ -149,6 +153,8 @@ RenderFrameHostImpl::RenderFrameHostImpl(SiteInstance* site_instance,
       override_sudden_termination_status_(false),
       is_waiting_for_beforeunload_ack_(false),
       unload_ack_is_for_navigation_(false),
+      is_loading_(false),
+      loading_progress_(kLoadingProgressNotStarted),
       accessibility_reset_token_(0),
       accessibility_reset_count_(0),
       no_create_browser_accessibility_manager_for_testing_(false),