DevTools: encapsulate presentation model in timeline view.

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

 var initialize_Timeline = function() {
 
 // Scrub values when printing out these properties in the record or data field.
 InspectorTest.timelinePropertyFormatters = {
     children: "formatAsTypeName",
     endTime: "formatAsTypeName",
     requestId: "formatAsTypeName",
     startTime: "formatAsTypeName",
     stackTrace: "formatAsTypeName",
     url: "formatAsURL",
@@ skipping 16 matching lines @@
     elementId: "formatAsTypeName",
     networkTime: "formatAsTypeName",
     thread: "formatAsTypeName"
 };
 
 InspectorTest.timelinePresentationModel = function()
 {
     return WebInspector.panels.timeline._currentViews[0]._presentationModel;
 }
 
+InspectorTest.timelineModel = function()
+{
+    return WebInspector.panels.timeline._model;
+}
+
 InspectorTest.startTimeline = function(callback)
 {
     InspectorTest._timelineRecords = [];
     WebInspector.panel("timeline").toggleTimelineButton.toggled = true;
     WebInspector.panel("timeline")._model._collectionEnabled = true;
     TimelineAgent.start(5, false, true, false, callback);
     function addRecord(record)
     {
         InspectorTest._timelineRecords.push(record);
         for (var i = 0; record.children && i < record.children.length; ++i)
@@ skipping 74 matching lines @@
     InspectorTest.evaluateWithTimeline(actions, callback)
 };
 
 InspectorTest.printTimelineRecords = function(typeName, formatter)
 {
     InspectorTest.innerPrintTimelineRecords(InspectorTest._timelineRecords, typeName, formatter);
 };
 
 InspectorTest.printTimestampRecords = function(typeName, formatter)
 {
-    InspectorTest.innerPrintTimelineRecords(InspectorTest.timelinePresentationModel().eventDividerRecords(), typeName, formatter);
+    InspectorTest.innerPrintTimelineRecords(InspectorTest.timelineModel().eventDividerRecords(), typeName, formatter);
 };
 
 InspectorTest.innerPrintTimelineRecords = function(records, typeName, formatter)
 {
     for (var i = 0; i < records.length; ++i) {
         if (typeName && records[i].type === WebInspector.TimelineModel.RecordType[typeName])
             InspectorTest.printTimelineRecordProperties(records[i]);
         if (formatter)
             formatter(records[i]);
     }
@@ skipping 139 matching lines @@
         return this._fileSize;
     },
 
     fileName: function()
     {
         return "fakeFile";
     }
 };
 
 };