[DevTools] Turn TracingManager into SDKModel.

third_party/WebKit/LayoutTests/http/tests/inspector/inspector-test.js

 if (window.GCController)
     GCController.collectAll();
 
 var initialize_InspectorTest = function() {
 Protocol.InspectorBackend.Options.suppressRequestErrors = true;
 var results = [];
 
 function consoleOutputHook(messageType)
 {
     InspectorTest.addResult(messageType + ": " + Array.prototype.slice.call(arguments, 1));
@@ skipping 960 matching lines @@
         InspectorTest.debuggerModel = SDK.DebuggerModel.fromTarget(target);
         InspectorTest.runtimeModel = target.runtimeModel;
         InspectorTest.domModel = SDK.DOMModel.fromTarget(target);
         InspectorTest.cssModel = target.model(SDK.CSSModel);
         InspectorTest.powerProfiler = target.powerProfiler;
         InspectorTest.cpuProfilerModel = target.model(SDK.CPUProfilerModel);
         InspectorTest.heapProfilerModel = target.heapProfilerModel;
         InspectorTest.animationModel = target.animationModel;
         InspectorTest.serviceWorkerCacheModel = target.serviceWorkerCacheModel;
         InspectorTest.serviceWorkerManager = target.model(SDK.ServiceWorkerManager);
-        InspectorTest.tracingManager = target.tracingManager;
+        InspectorTest.tracingManager = target.model(SDK.TracingManager);
         InspectorTest.mainTarget = target;
     },
 
     targetRemoved: function(target) { }
 });
 
 InspectorTest._panelsToPreload = [];
 
 InspectorTest.preloadPanel = function(panelName)
 {
@@ skipping 237 matching lines @@
     _output("[page] " + text);
 }
 
 function _output(result)
 {
     if (!outputElement)
         createOutputElement();
     outputElement.appendChild(document.createTextNode(result));
     outputElement.appendChild(document.createElement("br"));
 }