pointerActionSequence() always send MouseDown event with click_count=1 for "pointerDown".
pointerActionSequence() should send click_count=2 for double click and click_count=3 for
triple-click and more.

I could not find click count handling in "ui/events" in "cotnent/"
- int MouseEvent::GetRepeatCount(const MouseEvent& event)  in "ui/events/event.cc"
- WebMouseEventBuilder::Build() in "ui/events/blink/web_input_event_builders_win.cc"

It seems SyntheticMouseDriver::Press() set click_count to 1 and no code in content/
increases it.

Sample from http://crrev.com/2955543003
    chrome.gpuBenchmarking.pointerActionSequence(
      [{
        source: 'mouse',
        actions: [
          {
            name: 'pointerDown',
            button: 'left',
            x: clickX,
            y: clickY,
          },
          {name: 'pointerUp'},
          {name: 'pause'},
          {
            name: 'pointerDown',
            button: 'left',
            x: clickX,
            y: clickY,
          },
          {name: 'pointerUp'},
        ],
       }], resolve);