Add multifinger swipe event to TouchDispositionGestureFilter.

ui/events/gesture_detection/mock_motion_event.cc

Index: ui/events/gesture_detection/mock_motion_event.cc
diff --git a/ui/events/gesture_detection/mock_motion_event.cc b/ui/events/gesture_detection/mock_motion_event.cc
index 2cc8da738ac9c4f785d5d1ad32472ee2c38e7c6a..3ee63dffb4114596c148724a874064628208e6d8 100644
--- a/ui/events/gesture_detection/mock_motion_event.cc
+++ b/ui/events/gesture_detection/mock_motion_event.cc
@@ -137,7 +137,7 @@ void MockMotionEvent::PressPoint(float x, float y) {
   if (pointer_count == 1 && (action == ACTION_UP || action == ACTION_CANCEL))
     pointer_count = 0;
 
-  DCHECK_LT(pointer_count + 1, static_cast<size_t>(MAX_POINTERS));
+  DCHECK_LT(pointer_count, static_cast<size_t>(MAX_POINTERS));

[tdresser, 2014/04/25 19:26:48]

I believe this was a bug, can you double check?

[jdduke (slow), 2014/04/25 19:38:55]

It should be correct, note the |pointer_count++| call below (admittedly I'm not
proud of this code).

[tdresser, 2014/04/25 19:43:25]

So if I have 2 fingers down, and I press another finger, this currently
evaluates:

2 + 1 < 3 is false, and it doesn't let you press a third finger.
That's wrong, isn't it?

[jdduke (slow), 2014/04/25 19:45:26]

It evaluates 2 < 3, then does the increment.

[jdduke (slow), 2014/04/25 19:46:58]

Ugg, lol yeah I was checking *your* code, not the current code.  Looks good.

   points[pointer_count++] = gfx::PointF(x, y);
   action = pointer_count > 1 ? ACTION_POINTER_DOWN : ACTION_DOWN;
 }