Avoid exception when building details for DecodeImage event

Source/devtools/front_end/timeline/TracingTimelineUIUtils.js

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  */
 WebInspector.TracingTimelineUIUtils = function() { }
 
 /**
  * @constructor
@@ skipping 145 matching lines @@
         details = linkifyTopCallFrame();
         break;
     case recordType.EvaluateScript:
         var url = eventData["url"];
         if (url)
             details = linkifyLocation("", url, eventData["lineNumber"], 0);
         break;
     case recordType.XHRReadyStateChange:
     case recordType.XHRLoad:
     case recordType.ResourceSendRequest:
-    case recordType.DecodeImage:
-    case recordType.ResizeImage:
         var url = eventData["url"];
         if (url)
             detailsText = WebInspector.displayNameForURL(url);
         break;
     case recordType.ResourceReceivedData:
     case recordType.ResourceReceiveResponse:
     case recordType.ResourceFinish:
         var initiator = event.initiator;
         if (initiator) {
             var url = initiator.args.data["url"];
@@ skipping 359 matching lines @@
             callback();
             return;
         }
         var container = document.createElement("div");
         container.className = "image-preview-container";
         var img = container.createChild("img");
         img.src = encodedBitmap;
         callback(container);
     }
 }