[Icons NTP] Refactor large_icon_source to extract the logic shared between desktop and Android to f…

components/favicon_base/favicon_callback.h

Index: components/favicon_base/favicon_callback.h
diff --git a/components/favicon_base/favicon_callback.h b/components/favicon_base/favicon_callback.h
index 7616a113feefca47ea742e0ae03b8796efd99cc7..4b6973b0cf58e2e5cbf123d180f7564ac967ab3f 100644
--- a/components/favicon_base/favicon_callback.h
+++ b/components/favicon_base/favicon_callback.h
@@ -13,6 +13,7 @@ namespace favicon_base {
 
 struct FaviconRawBitmapResult;
 struct FaviconImageResult;
+struct LargeIconResult;
 
 // Callback for functions that can be used to return a |gfx::Image| and the
 // |GURL| it is loaded from. They are returned as a |FaviconImageResult| object.
@@ -29,6 +30,11 @@ typedef base::Callback<void(const FaviconRawBitmapResult&)>
 typedef base::Callback<void(const std::vector<FaviconRawBitmapResult>&)>
     FaviconResultsCallback;
 
+// Callback for functions returning data for a large icon. |LargeIconResult|
+// will contain either the raw bitmap for a large icon or the dominant color of
+// a small favicon if a large icon of the desired size could not be found.
+typedef base::Callback<void(const LargeIconResult&)> LargeIconCallback;
+
 }  // namespace favicon_base
 
 #endif  // COMPONENTS_FAVICON_BASE_FAVICON_CALLBACK_H_