Chrome requires WebTouchPoint to store WebFloatPoint, instead of WebPoint.

content/browser/renderer_host/input/touch_event_queue.cc

Index: content/browser/renderer_host/input/touch_event_queue.cc
diff --git a/content/browser/renderer_host/input/touch_event_queue.cc b/content/browser/renderer_host/input/touch_event_queue.cc
index c863d299a5e27c467cd120e0190849a4bfac62ed..a6d8729f49c23f8df07303ebe487928a28d8cbb8 100644
--- a/content/browser/renderer_host/input/touch_event_queue.cc
+++ b/content/browser/renderer_host/input/touch_event_queue.cc
@@ -169,17 +169,15 @@ class TouchEventQueue::TouchTimeoutHandler {
 // a given slop region, unless the touchstart is preventDefault'ed.
 class TouchEventQueue::TouchMoveSlopSuppressor {
  public:
-  // TODO(jdduke): Remove int cast on suppression length, crbug.com/336807.
   TouchMoveSlopSuppressor(double slop_suppression_length_dips)
-      : slop_suppression_length_dips_squared_(
-            static_cast<int>(slop_suppression_length_dips) *
-            static_cast<int>(slop_suppression_length_dips)),
+      : slop_suppression_length_dips_squared_(slop_suppression_length_dips *
+                                              slop_suppression_length_dips),
         suppressing_touch_moves_(false) {}
 
   bool FilterEvent(const WebTouchEvent& event) {
     if (WebTouchEventTraits::IsTouchSequenceStart(event)) {
       touch_sequence_start_position_ =

[jdduke (slow), 2014/03/10 22:03:23]

Hmm, does this fit on one line now?

[tdresser, 2014/03/12 13:54:40]

Yup, done.

-          gfx::PointF(event.touches[0].position.x, event.touches[0].position.y);
+          gfx::PointF(event.touches[0].position);
       suppressing_touch_moves_ = slop_suppression_length_dips_squared_ != 0;
     }
 
@@ -192,11 +190,9 @@ class TouchEventQueue::TouchMoveSlopSuppressor {
         suppressing_touch_moves_ = false;
       } else if (event.touchesLength == 1) {
         // Movement outside of the slop region should terminate suppression.
-        // TODO(jdduke): Use strict inequality, crbug.com/336807.
-        gfx::PointF position(event.touches[0].position.x,
-                             event.touches[0].position.y);
-        if ((position - touch_sequence_start_position_).LengthSquared() >=
-                slop_suppression_length_dips_squared_)
+        gfx::PointF position(event.touches[0].position);
+        if ((position - touch_sequence_start_position_).LengthSquared() >

[jdduke (slow), 2014/03/10 22:03:23]

So, I'm wondering if we'll run into floating point issues here... Sadly, I'm not
sure there's an easy way around that other than converting back to pixels and
doing the test on properly rounded integral values.  It might be worth adding a
short test that checks the inclusive slop region using scaling factors of 1.5
and .75 on coordinates larger than, say, 1000 (where coords outside the region
by some small epsilon are not suppressed).

[tdresser, 2014/03/12 13:54:40]

That's unfortunate. Good call though. Rounding broke one previous test:
TouchEventQueueTest.TouchMoveSuppressionWithinSlopRegion. I think the change to
fix it is reasonable, but can you double check it? Rounding means that in some
cases you need to exceed the slop more than was necessary previously in order to
stop suppressing touch moves.

+            slop_suppression_length_dips_squared_)
           suppressing_touch_moves_ = false;
       }
     }