[DevTools] Make resource tree model optional

third_party/WebKit/Source/devtools/front_end/components/DOMPresentationUtils.js

 /*
  * Copyright (C) 2011 Google Inc.  All rights reserved.
  * Copyright (C) 2007, 2008 Apple Inc.  All rights reserved.
  * Copyright (C) 2008 Matt Lilek <webkit@mattlilek.com>
  * Copyright (C) 2009 Joseph Pecoraro
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
@@ skipping 141 matching lines @@
 
 /**
  * @param {!WebInspector.Target} target
  * @param {string} originalImageURL
  * @param {boolean} showDimensions
  * @param {function(!Element=)} userCallback
  * @param {!Object=} precomputedFeatures
  */
 WebInspector.DOMPresentationUtils.buildImagePreviewContents = function(target, originalImageURL, showDimensions, userCallback, precomputedFeatures)
 {
-    var resource = target.resourceTreeModel.resourceForURL(originalImageURL);
+    var resourceTreeModel = WebInspector.ResourceTreeModel.fromTarget(target);
+    if (!resourceTreeModel) {
+        userCallback();
+        return;
+    }
+    var resource = resourceTreeModel.resourceForURL(originalImageURL);
     var imageURL = originalImageURL;
     if (!isImageResource(resource) && precomputedFeatures && precomputedFeatures.currentSrc) {
         imageURL = precomputedFeatures.currentSrc;
-        resource = target.resourceTreeModel.resourceForURL(imageURL);
+        resource = resourceTreeModel.resourceForURL(imageURL);
     }
     if (!isImageResource(resource)) {
         userCallback();
         return;
     }
 
     var imageElement = createElement("img");
     imageElement.addEventListener("load", buildContent, false);
     imageElement.addEventListener("error", errorCallback, false);
     resource.populateImageSource(imageElement);
@@ skipping 476 matching lines @@
     /**
      * @override
      * @param {!WebInspector.DOMNode} node
      * @return {?{title: string, color: string}}
      */
     decorate: function(node)
     {
         return { title: this._title, color: this._color };
     }
 }