DevTools: Cache the original content on UISourceCode

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

 /*
  * Copyright (C) 2012 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 86 matching lines @@
    */
   requestMetadata(uiSourceCode) {},
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {function(?string)} callback
    */
   requestFileContent(uiSourceCode, callback) {},
 
   /**
+   * @param {!Workspace.UISourceCode} uiSourceCode
+   * @return {!Promise<?string>}
+   */
+  requestOriginalFileContent(uiSourceCode) {},
+
+  /**
    * @return {boolean}
    */
   canSetFileContent() {},
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
    * @param {string} newContent
-   * @param {function(?string)} callback
+   * @param {function()} callback
    */
   setFileContent(uiSourceCode, newContent, callback) {},
 
   /**
    * @return {boolean}
    */
   canRename() {},
 
   /**
    * @param {!Workspace.UISourceCode} uiSourceCode
@@ skipping 326 matching lines @@
   WorkingCopyCommitted: Symbol('WorkingCopyCommitted'),
   WorkingCopyCommittedByUser: Symbol('WorkingCopyCommittedByUser'),
   ProjectAdded: Symbol('ProjectAdded'),
   ProjectRemoved: Symbol('ProjectRemoved')
 };
 
 /**
  * @type {!Workspace.Workspace}
  */
 Workspace.workspace;