Timeline: add preview of painted picture for Paint event

Source/devtools/front_end/timeline/TimelineModel.js

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 125 matching lines @@
             if (postOrderCallback && postOrderCallback(record, depth))
                 return true;
         }
         return false;
     }
     return processRecords(recordsArray, 0);
 }
 
 WebInspector.TimelineModel.prototype = {
     /**
+     * @param {boolean} captureStacks
+     * @param {boolean} captureMemory
+     * @param {boolean} capturePictures
+     */
+    startRecording: function(captureStacks, captureMemory, capturePictures)
+    {
+    },
+
+    stopRecording: function()
+    {
+    },
+
+    /**
      * @return {boolean}
      */
     loadedFromFile: function()
     {
         return false;
     },
 
     /**
      * @param {?function(!WebInspector.TimelineModel.Record)|?function(!WebInspector.TimelineModel.Record,number)} preOrderCallback
      * @param {function(!WebInspector.TimelineModel.Record)|function(!WebInspector.TimelineModel.Record,number)=} postOrderCallback
@@ skipping 335 matching lines @@
         function recordTimestampComparator(a, b)
         {
             // Never return 0, as the merge function will squash identical entries.
             return a.startTime() < b.startTime() ? -1 : 1;
         }
         var result = this._backgroundRecordsBuffer.mergeOrdered(records, recordTimestampComparator);
         this._backgroundRecordsBuffer = [];
         return result;
     }
 }