Fix NTP thumbnail generation

chrome/browser/thumbnails/thumbnailing_context.h

Index: chrome/browser/thumbnails/thumbnailing_context.h
diff --git a/chrome/browser/thumbnails/thumbnailing_context.h b/chrome/browser/thumbnails/thumbnailing_context.h
index 1cfe67178aeb2a2270510a0da26cb12058efddb8..5a912c57153ea38bcf75b909d31ff25a9aec7134 100644
--- a/chrome/browser/thumbnails/thumbnailing_context.h
+++ b/chrome/browser/thumbnails/thumbnailing_context.h
@@ -45,6 +45,7 @@ struct ThumbnailingContext : base::RefCountedThreadSafe<ThumbnailingContext> {
   }
 
   scoped_refptr<ThumbnailService> service;
+  content::WebContents* web_contents;

[Lei Zhang, 2015/10/07 17:55:20]

I added motek because git blame says he wrote this entire file. I'm not sure
what the lifetime of ThumbnailingContext is, so I don't know if it's safe to
store a raw WebContents* here.

[shrike, 2015/10/07 18:06:34]

Sounds good - I don't know the answer either.

   GURL url;
   ClipResult clip_result;
   gfx::Size requested_copy_size;