[NTP Tiles] Fetch missing MostLikely tiles from a Google server

components/favicon_base/favicon_types.h

 // Copyright 2014 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 COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_
 #define COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_
 
 #include <stdint.h>
 
 #include <memory>
@@ skipping 72 matching lines @@
 // either the bitmap data if the favicon database has a sufficiently large
 // favicon bitmap and the style of the fallback icon otherwise.
 struct LargeIconResult {
   explicit LargeIconResult(const FaviconRawBitmapResult& bitmap_in);
 
   // Takes ownership of |fallback_icon_style_in|.
   explicit LargeIconResult(FallbackIconStyle* fallback_icon_style_in);
 
   ~LargeIconResult();
 
+  // Returns true if the LargeIconResult contains no data (neither in |bitmap|,
+  // nor in |fallback_icon_style|).
+  bool is_empty() const;
+
   // The bitmap from the favicon database if the database has a sufficiently
   // large one.
   FaviconRawBitmapResult bitmap;
 
   // The fallback icon style if a sufficiently large icon isn't available. This
   // uses the dominant color of a smaller icon as the background if available.
   std::unique_ptr<FallbackIconStyle> fallback_icon_style;
 };
 
 // Result returned by LargeIconService::GetLargeIconImageOrFallbackStyle().
@@ skipping 12 matching lines @@
   gfx::Image image;
 
   // The fallback icon style if a sufficiently large icon isn't available. This
   // uses the dominant color of a smaller icon as the background if available.
   std::unique_ptr<FallbackIconStyle> fallback_icon_style;
 };
 
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_TYPES_H_