[Doodle] Don't create invalid DoodleImages or DoodleConfigs

components/doodle/doodle_types.h

 // Copyright 2017 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_DOODLE_DOODLE_TYPES_H_
 #define COMPONENTS_DOODLE_DOODLE_TYPES_H_
 
 #include "base/optional.h"
 #include "url/gurl.h"
 
@@ skipping 13 matching lines @@
 enum class DoodleType {
   UNKNOWN,
   SIMPLE,
   RANDOM,
   VIDEO,
   INTERACTIVE,
   INLINE_INTERACTIVE,
   SLIDESHOW,
 };
 
-// Information about a Doodle image. If the image is invalid, the |url| will be
-// empty and invalid. By default the dimensions are 0.
+// Information about a Doodle image. By default the dimensions are 0.
 struct DoodleImage {
-  DoodleImage();
+  DoodleImage(const GURL& url);
   ~DoodleImage();
 
   static base::Optional<DoodleImage> FromDictionary(
       const base::DictionaryValue& dict,
       const base::Optional<GURL>& base_url);
 
   bool operator==(const DoodleImage& other) const;
   bool operator!=(const DoodleImage& other) const;
 
   GURL url;
   int height;
   int width;
   bool is_animated_gif;
   bool is_cta;
 
   // Copying and assignment allowed.
 };
 
 // All information about a current doodle that can be fetched from the remote
 // end. By default, all URLs are empty and therefore invalid.
 struct DoodleConfig {
-  DoodleConfig();
+  DoodleConfig(DoodleType doodle_type, const DoodleImage& large_image);
   DoodleConfig(const DoodleConfig& config);  // = default;
   ~DoodleConfig();
 
   static base::Optional<DoodleConfig> FromDictionary(
       const base::DictionaryValue& dict,
       const base::Optional<GURL>& base_url);
 
   bool operator==(const DoodleConfig& other) const;
   bool operator!=(const DoodleConfig& other) const;
 
   DoodleType doodle_type;
   std::string alt_text;
   std::string interactive_html;
 
   GURL search_url;
   GURL target_url;
   GURL fullpage_interactive_url;
 
   DoodleImage large_image;
-  DoodleImage large_cta_image;
-  DoodleImage transparent_large_image;
+  base::Optional<DoodleImage> large_cta_image;
+  base::Optional<DoodleImage> transparent_large_image;
 
   // Copying and assignment allowed.
 };
 
 }  // namespace doodle
 
 #endif  // COMPONENTS_DOODLE_DOODLE_TYPES_H_