DevTools: Cache the original content on UISourceCode

third_party/WebKit/Source/devtools/front_end/workspace/UISourceCode.js

 /*
  * Copyright (C) 2011 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 271 matching lines @@
   }
 
   forceLoadOnCheckContent() {
     this._forceLoadOnCheckContent = true;
   }
 
   /**
    * @return {!Promise<?string>}
    */
   requestOriginalContent() {
-    var callback;
-    var promise = new Promise(fulfill => callback = fulfill);
-    this._project.requestFileContent(this, callback);
-    return promise;
+    return this._project.requestOriginalFileContent(this);
   }
 
   /**
    * @param {string} content
    */
   _commitContent(content) {
     if (this._project.canSetFileContent()) {
       this._project.setFileContent(this, content, function() {});
     } else if (this._url && Workspace.fileManager.isURLSaved(this._url)) {
       Workspace.fileManager.save(this._url, content, false, function() {});
@@ skipping 601 matching lines @@
 Workspace.UISourceCodeMetadata = class {
   /**
    * @param {?Date} modificationTime
    * @param {?number} contentSize
    */
   constructor(modificationTime, contentSize) {
     this.modificationTime = modificationTime;
     this.contentSize = contentSize;
   }
 };