Extract minimal RenderViewHost interface for embedders, leaving

chrome/browser/tab_contents/thumbnail_generator.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/tab_contents/thumbnail_generator.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/memory/scoped_ptr.h"
@@ skipping 464 matching lines @@
 
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   history::TopSites* top_sites = profile->GetTopSites();
   if (!top_sites)
     return;
 
   // Compute the thumbnail score.
   ThumbnailScore score;
   score.at_top =
-      (web_contents->GetRenderViewHost()->last_scroll_offset().y() == 0);
+      (web_contents->GetRenderViewHost()->GetLastScrollOffset().y() == 0);
   score.boring_score = ThumbnailGenerator::CalculateBoringScore(&thumbnail);
   score.good_clipping =
       (clip_result == ThumbnailGenerator::kTallerThanWide ||
        clip_result == ThumbnailGenerator::kNotClipped);
   score.load_completed = (!load_interrupted_ && !web_contents->IsLoading());
 
   gfx::Image image(new SkBitmap(thumbnail));
   const GURL& url = web_contents->GetURL();
   top_sites->SetPageThumbnail(url, &image, score);
   VLOG(1) << "Thumbnail taken for " << url << ": " << score.ToString();
@@ skipping 30 matching lines @@
 
 void ThumbnailGenerator::DidStartLoading() {
   load_interrupted_ = false;
 }
 
 void ThumbnailGenerator::StopNavigation() {
   // This function gets called when the page loading is interrupted by the
   // stop button.
   load_interrupted_ = true;
 }