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

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index 1926ce3a0fe8e7cf5f247745a22367c13a326385..082fa62d7a87486c97d394500d31d1123c22ae70 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -89,6 +89,10 @@ class PrerenderContents : public content::NotificationObserver,
     // destroyed.
     virtual void OnPrerenderStop(PrerenderContents* contents) {}
 
+    // Signals that a resource finished loading and altered the running byte
+    // count.
+    virtual void OnPrerenderNetworkBytesChanged(PrerenderContents* contents) {}
+
    protected:
     Observer() {}
     virtual ~Observer() = 0;
@@ -238,6 +242,9 @@ class PrerenderContents : public content::NotificationObserver,
     return prerendering_has_been_cancelled_;
   }
 
+  // Running byte count. Increased when each resource completes loading.
+  int64_t network_bytes() { return network_bytes_; }
+
  protected:
   PrerenderContents(PrerenderManager* prerender_manager,
                     Profile* profile,