code: function(eventName, cpuNumber, pid, ts, eventBase) {
        var innerEvent =
            /^\s*(\w+):\s*(\w+)$/.exec(eventBase.details);
        switch (innerEvent[1]) {
          case 'start':
            this.gestureOpenSlice('GestureLog', ts, {name: innerEvent[2]});
            break;
          case 'end':
            this.gestureCloseSlice('GestureLog', ts);
        }
        return true;
      }
docs: For log events, events will come in pairs with a tag log:
  like this:
  tracing_mark_write: log: start: TimerLogOutputs
  tracing_mark_write: log: end: TimerLogOutputs
  which represent the start and the end time of certain log behavior
  Take these logs above for example, they are the start and end time
  of logging Output for HandleTimer function