Reland fix for thumbnail generation.

chrome/browser/thumbnails/thumbnail_service.h

 // 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.
 
 #ifndef CHROME_BROWSER_THUMBNAILS_THUMBNAIL_SERVICE_H_
 #define CHROME_BROWSER_THUMBNAILS_THUMBNAIL_SERVICE_H_
 
 #include "components/history/core/common/thumbnail_score.h"
 #include "components/keyed_service/core/refcounted_keyed_service.h"
 #include "ui/gfx/image/image.h"
 
 class GURL;
 
 namespace base {
 class RefCountedMemory;
 }
 
 namespace thumbnails {
 
 class ThumbnailingAlgorithm;
-struct ThumbnailingContext;
+class ThumbnailingContext;
 
 // An interface abstracting access to thumbnails. Intended as a temporary
 // bridge facilitating switch from TopSites as the thumbnail source to a more
 // robust way of handling these artefacts.
 class ThumbnailService : public RefcountedKeyedService {
  public:
   // Sets the given thumbnail for the given URL. Returns true if the thumbnail
   // was updated. False means either the URL wasn't known to us, or we felt
   // that our current thumbnail was superior to the given one.
   virtual bool SetPageThumbnail(const ThumbnailingContext& context,
@@ skipping 25 matching lines @@
   // Returns true if the page thumbnail should be updated.
   virtual bool ShouldAcquirePageThumbnail(const GURL& url) = 0;
 
  protected:
   ~ThumbnailService() override {}
 };
 
 }  // namespace thumbnails
 
 #endif  // CHROME_BROWSER_THUMBNAILS_THUMBNAIL_SERVICE_H_