Refactor the API for setting dynamic resource load priorities

Source/platform/network/ResourceLoadPriority.h

 /*
  * Copyright (C) 2010 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 23 matching lines @@
     ResourceLoadPriorityUnresolved = -1,
     ResourceLoadPriorityVeryLow = 0,
     ResourceLoadPriorityLow,
     ResourceLoadPriorityMedium,
     ResourceLoadPriorityHigh,
     ResourceLoadPriorityVeryHigh,
     ResourceLoadPriorityLowest = ResourceLoadPriorityVeryLow,
     ResourceLoadPriorityHighest = ResourceLoadPriorityVeryHigh,
 };
 
+struct ResourcePriority {
+public:
+    enum VisibilityStatus {
+        NotVisible,
+        Visible,
+    };
+
+    ResourcePriority() : ResourcePriority(NotVisible, 0) { }
+    ResourcePriority(VisibilityStatus status, int intraValue)
+        : visibility(status)
+        , intraPriorityValue(intraValue)
+    {
+    }
+
+    VisibilityStatus visibility;
+    int intraPriorityValue;
+};
+
 }
 
 #endif