DevTools: make StylesSourceMapping in charge of creating and removing UISourceCodes

third_party/WebKit/Source/devtools/front_end/bindings/ResourceUtils.js

 /*
  * Copyright (C) 2006, 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2007 Matt Lilek (pewtermoose@gmail.com).
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * 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
@@ skipping 68 matching lines @@
     if (url.startsWith(baseURL))
       return url.substring(index);
   }
 
   if (!parsedURL)
     return url;
 
   var displayName = url.trimURL(parsedURL.host);
   return displayName === '/' ? parsedURL.host + '/' : displayName;
 };
+
+/**
+ * @param {?SDK.Resource} resource
+ * @return {?Workspace.UISourceCodeMetadata}
+ */
+Bindings.resourceMetadata = function(resource) {
+  if (!resource || (typeof resource.contentSize() !== 'number' && !resource.lastModified()))
+    return null;
+  return new Workspace.UISourceCodeMetadata(resource.lastModified(), resource.contentSize());
+};