DevTools: Sources: Use URL over content for drag and drop on files.

third_party/WebKit/Source/devtools/front_end/sources/NavigatorView.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:
  *
  * 1. Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *
@@ skipping 925 matching lines @@
     return this._uiSourceCode;
   }
 
   /**
    * @override
    */
   onattach() {
     this.listItemElement.draggable = true;
     this.listItemElement.addEventListener('click', this._onclick.bind(this), false);
     this.listItemElement.addEventListener('contextmenu', this._handleContextMenuEvent.bind(this), false);
-    this.listItemElement.addEventListener('mousedown', this._onmousedown.bind(this), false);
     this.listItemElement.addEventListener('dragstart', this._ondragstart.bind(this), false);
   }
 
-  _onmousedown(event) {
-    if (event.which === 1)  // Warm-up data for drag'n'drop
-      this._uiSourceCode.requestContent().then(callback.bind(this));
-    /**
-     * @param {?string} content
-     * @this {Sources.NavigatorSourceTreeElement}
-     */
-    function callback(content) {
-      this._warmedUpContent = content;
-    }
-  }
-
   _shouldRenameOnMouseDown() {
     if (!this._uiSourceCode.canRename())
       return false;
     var isSelected = this === this.treeOutline.selectedTreeElement;
     return isSelected && this.treeOutline.element.hasFocus() && !UI.isBeingEdited(this.treeOutline.element);
   }
 
   /**
    * @override
    */
   selectOnMouseDown(event) {
     if (event.which !== 1 || !this._shouldRenameOnMouseDown()) {
       super.selectOnMouseDown(event);
       return;
     }
     setTimeout(rename.bind(this), 300);
 
     /**
      * @this {Sources.NavigatorSourceTreeElement}
      */
     function rename() {
       if (this._shouldRenameOnMouseDown())
         this._navigatorView.rename(this.uiSourceCode, false);
     }
   }
 
+  /**
+   * @param {!DragEvent} event
+   */
   _ondragstart(event) {
-    event.dataTransfer.setData('text/plain', this._warmedUpContent);
+    event.dataTransfer.setData('text/plain', this._uiSourceCode.url());
     event.dataTransfer.effectAllowed = 'copy';
-    return true;
   }
 
   /**
    * @override
    * @return {boolean}
    */
   onspace() {
     this._navigatorView._sourceSelected(this.uiSourceCode, true);
     return true;
   }
@@ skipping 592 matching lines @@
   /**
    * @param {string} title
    * @override
    */
   setTitle(title) {
     this._title = title;
     if (this._treeElement)
       this._treeElement.title = this._title;
   }
 };