DevTools: Rename WebInspector.DOMAgent into WebInspector.DOMModel

LayoutTests/http/tests/inspector/layers-test.js

 function initialize_LayerTreeTests()
 {
     // FIXME: remove once out of experimental.
     WebInspector.moduleManager.registerModule("layers");
     var extensions = WebInspector.moduleManager.extensions(WebInspector.Panel).forEach(function(extension) {
         if (extension.module().name() === "layers")
             WebInspector.inspectorView.addPanel(new WebInspector.ModuleManagerExtensionPanelDescriptor(extension));
     });
     InspectorTest.layerTreeModel = WebInspector.inspectorView.panel("layers")._model;
 
     InspectorTest.labelForLayer = function(layer)
     {
-        var node = WebInspector.domAgent.nodeForId(layer.nodeIdForSelfOrAncestor());
+        var node = WebInspector.domModel.nodeForId(layer.nodeIdForSelfOrAncestor());
         var label = node ? WebInspector.DOMPresentationUtils.fullQualifiedSelector(node, false) : "<invalid node id>";
         var height = layer.height();
         var width = layer.width();
         if (height <= 200 && width <= 200)
             label += " " + height + "x" + width;
         if (typeof layer.__extraData !== "undefined")
             label += " (" + layer.__extraData + ")";
         return label;
     }
 
@@ skipping 48 matching lines @@
         });
     }
 
     InspectorTest.findLayerByNodeIdAttribute = function(nodeIdAttribute)
     {
         var result;
         function testLayer(layer)
         {
             if (!layer.nodeId())
                 return false;
-            var node = WebInspector.domAgent.nodeForId(layer.nodeId());
+            var node = WebInspector.domModel.nodeForId(layer.nodeId());
             if (!node || node.getAttribute("id") !== nodeIdAttribute)
                 return false;
             result = layer;
             return true;
         }
         InspectorTest.layerTreeModel.forEachLayer(testLayer);
         if (!result)
             InspectorTest.addResult("ERROR: No layer for " + nodeIdAttribute);
         return result;
     }
@@ skipping 35 matching lines @@
     {
         function dumpScrollRectsForLayer(layer)
         {
             InspectorTest.addObject(layer._scrollRects);
         }
 
         InspectorTest.addResult("Model elements dump");
         InspectorTest.layerTreeModel.forEachLayer(dumpScrollRectsForLayer.bind(this));
     }
 }