[Offline Pages] Make prerenderer notify us of network progress.

chrome/browser/prerender/prerender_handle.h

Index: chrome/browser/prerender/prerender_handle.h
diff --git a/chrome/browser/prerender/prerender_handle.h b/chrome/browser/prerender/prerender_handle.h
index 9beac512926dbd67042a6895a587e61686aeb9d8..e16fed1dd8247195584b9013b3f8a81743ff6542 100644
--- a/chrome/browser/prerender/prerender_handle.h
+++ b/chrome/browser/prerender/prerender_handle.h
@@ -38,6 +38,10 @@ class PrerenderHandle : public PrerenderContents::Observer {
     // Signals that the prerender has stopped running.
     virtual void OnPrerenderStop(PrerenderHandle* handle) = 0;
 
+    // Signals that a resource finished loading and altered the running byte
+    // count.
+    virtual void OnPrerenderNetworkBytesChanged(PrerenderHandle* handle) = 0;
+
    protected:
     Observer();
     virtual ~Observer();
@@ -86,6 +90,8 @@ class PrerenderHandle : public PrerenderContents::Observer {
   void OnPrerenderDomContentLoaded(
       PrerenderContents* prerender_contents) override;
   void OnPrerenderStop(PrerenderContents* prerender_contents) override;
+  void OnPrerenderNetworkBytesChanged(
+      PrerenderContents* prerender_contents) override;
 
   Observer* observer_;