DevTools: introduce dom markers, decorate hidden, forced state and breakpoint elements using marker…

LayoutTests/inspector/elements/edit/set-outer-html-test.js

 var initialize_SetOuterHTMLTest = function() {
 
 InspectorTest.events = [];
 InspectorTest.containerId;
 
 InspectorTest.setUpTestSuite = function(next)
 {
     InspectorTest.expandElementsTree(step1);
 
     function step1()
@@ skipping 15 matching lines @@
             var eventName = WebInspector.DOMModel.Events[key];
             InspectorTest.domModel.addEventListener(eventName, InspectorTest.recordEvent.bind(InspectorTest, eventName));
         }
 
         next();
     }
 }
 
 InspectorTest.recordEvent = function(eventName, event)
 {
-    if (!event.data)
+    if (!event.data || event.type === WebInspector.DOMModel.Events.MarkersChanged)
         return;
     var node = event.data.node || event.data;
     var parent = event.data.parent;
     for (var currentNode = parent || node; currentNode; currentNode = currentNode.parentNode) {
         if (currentNode.getAttribute("id") === "output")
             return;
     }
     InspectorTest.events.push("Event " + eventName + ": " + node.nodeName());
 }
 
@@ skipping 55 matching lines @@
         InspectorTest.addResult("==========8<==========");
         InspectorTest.addResult(text);
         InspectorTest.addResult("==========>8==========");
         if (last)
             InspectorTest.addResult("\n\n\n");
         next();
     }
 }
 
 };