[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..59b0ad4880f0e868ae493a587c7deaeaf12e7fb0 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 +242,8 @@ class PrerenderContents : public content::NotificationObserver,
     return prerendering_has_been_cancelled_;
   }
 
+  int64_t network_bytes() { return network_bytes_; }

[pasko-google - do not use, 2017/02/22 13:32:44]

I think it would be useful to link from here to some other description about
precision/limitations of the way we count network bytes. But the reference
itself might be long or ambiguous. If you like this comment, please do whatever
looks appropriate to you.

Very nit. Much rant. Wow.

[Dmitry Titov, 2017/02/23 04:27:54]

Done. I tried.

[pasko, 2017/02/24 15:10:28]

the new description is OK. I asked for a more detailed comment because I did not
know a central place where caveats like "we don't count TLS overhead" are
mentioned. If there is no easy place, let's keep it as you last suggested.

[Dmitry Titov, 2017/02/24 19:09:13]

Acknowledged.

+
  protected:
   PrerenderContents(PrerenderManager* prerender_manager,
                     Profile* profile,