Generate thumbnails in the browser process.

chrome/browser/renderer_host/render_view_host_delegate.h

Index: chrome/browser/renderer_host/render_view_host_delegate.h
diff --git a/chrome/browser/renderer_host/render_view_host_delegate.h b/chrome/browser/renderer_host/render_view_host_delegate.h
index e3ddf6317ddf61e0ea40d95c4907fded0b25af0f..34574fdd1470f60041ecfdab2e13798d2015f482 100644
--- a/chrome/browser/renderer_host/render_view_host_delegate.h
+++ b/chrome/browser/renderer_host/render_view_host_delegate.h
@@ -614,11 +614,6 @@ class RenderViewHostDelegate : public IPC::Channel::Listener {
   // The destination URL has changed should be updated
   virtual void UpdateTargetURL(int32 page_id, const GURL& url) {}
 
-  // The thumbnail representation of the page changed and should be updated.
-  virtual void UpdateThumbnail(const GURL& url,
-                               const SkBitmap& bitmap,
-                               const ThumbnailScore& score) {}
-
   // Inspector setting was changed and should be persisted.
   virtual void UpdateInspectorSetting(const std::string& key,
                                       const std::string& value) = 0;