DevTools: introduce uiSourceCode.mimeType() method

third_party/WebKit/Source/devtools/front_end/snippets/ScriptSnippetModel.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 534 matching lines @@
     super(workspace, 'snippets:', Workspace.projectTypes.Snippets, '', false /* isServiceProject */);
     this._model = model;
   }
 
   /**
    * @param {string} name
    * @param {!Common.ContentProvider} contentProvider
    * @return {!Workspace.UISourceCode}
    */
   addSnippet(name, contentProvider) {
-    return this.addContentProvider(name, contentProvider);
+    return this.addContentProvider(name, contentProvider, 'text/javascript');
   }
 
   /**
    * @override
    * @return {boolean}
    */
   canSetFileContent() {
     return true;
   }
 
@@ skipping 43 matching lines @@
    */
   deleteFile(uiSourceCode) {
     this._model.deleteScriptSnippet(uiSourceCode);
   }
 };
 
 /**
  * @type {!Snippets.ScriptSnippetModel}
  */
 Snippets.scriptSnippetModel = new Snippets.ScriptSnippetModel(Workspace.workspace);