[WIP] Use Optional<SkColor> instead of int64 for colors in Manifest.

content/public/common/manifest.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 CONTENT_PUBLIC_COMMON_MANIFEST_H_
 #define CONTENT_PUBLIC_COMMON_MANIFEST_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
 
+#include "base/optional.h"
 #include "base/strings/nullable_string16.h"
 #include "content/common/content_export.h"
 #include "third_party/WebKit/public/platform/WebDisplayMode.h"
 #include "third_party/WebKit/public/platform/modules/screen_orientation/WebScreenOrientationLockType.h"
+#include "third_party/skia/include/core/SkColor.h"
 #include "ui/gfx/geometry/size.h"
 #include "url/gurl.h"
 
 namespace content {
 
 // The Manifest structure is an internal representation of the Manifest file
 // described in the "Manifest for Web Application" document:
 // http://w3c.github.io/manifest/
 struct CONTENT_EXPORT Manifest {
   // Structure representing an icon as per the Manifest specification, see:
@@ skipping 72 matching lines @@
   // Empty if the parsing failed, the field was not present, empty or all the
   // applications inside the array were invalid. The order of the array
   // indicates the priority of the application to use.
   std::vector<RelatedApplication> related_applications;
 
   // A boolean that is used as a hint for the user agent to say that related
   // applications should be preferred over the web application. False if missing
   // or there is a parsing failure.
   bool prefer_related_applications;
 
-  // This is a 64 bit integer because we need to represent an error state. The
-  // color itself should only be 32 bits long if the value is not
-  // kInvalidOrMissingColor and can be safely cast to SkColor if is valid.
-  // Set to kInvalidOrMissingColor if parsing failed or field is not
-  // present.
-  int64_t theme_color;
+  // The Optional is empty if no value was present or if it was invalid. It is
+  // a valid SkColor otherwise.
+  base::Optional<SkColor> theme_color;
 
-  // This is a 64 bit integer because we need to represent an error state. The
-  // color itself should only be 32 bits long if the value is not
-  // kInvalidOrMissingColor and can be safely cast to SkColor if is valid.
-  // Set to kInvalidOrMissingColor if parsing failed or field is not
-  // present.
-  int64_t background_color;
+  // The Optional is empty if no value was present or if it was invalid. It is
+  // a valid SkColor otherwise.
+  base::Optional<SkColor> background_color;
 
   // This is a proprietary extension of the web Manifest, double-check that it
   // is okay to use this entry.
   // Null if parsing failed or the field was not present.
   base::NullableString16 gcm_sender_id;
 
   // Empty if the parsing failed or the field was not present.
   GURL scope;
 
   // Maximum length for all the strings inside the Manifest when it is sent over
   // IPC. The renderer process should truncate the strings before sending the
   // Manifest and the browser process must do the same when receiving it.
   static const size_t kMaxIPCStringLength;
-
-  // Constant representing an invalid color. Set to a value outside the
-  // range of a 32-bit integer.
-  static const int64_t kInvalidOrMissingColor;
 };
 
 } // namespace content
 
 #endif // CONTENT_PUBLIC_COMMON_MANIFEST_H_