Add tangentialPressure and twist properties to PointerEvent on Mac

third_party/WebKit/public/platform/WebPointerProperties.h

Index: third_party/WebKit/public/platform/WebPointerProperties.h
diff --git a/third_party/WebKit/public/platform/WebPointerProperties.h b/third_party/WebKit/public/platform/WebPointerProperties.h
index 0373dac2f1f564877baaa8bca80f82ff6c7109ac..b23d37992da894f67779c40bbd730ca67ff8cd5e 100644
--- a/third_party/WebKit/public/platform/WebPointerProperties.h
+++ b/third_party/WebKit/public/platform/WebPointerProperties.h
@@ -22,6 +22,8 @@ class WebPointerProperties {
         force(std::numeric_limits<float>::quiet_NaN()),
         tiltX(0),
         tiltY(0),
+        tangentialPressure(0.0f),
+        twist(0),
         button(Button::NoButton),
         pointerType(PointerType::Unknown) {}
 
@@ -58,6 +60,16 @@ class WebPointerProperties {
   int tiltX;
   int tiltY;
 
+  // The normalized tangential pressure, typically set by an additional control
+  // of the stylus, which has a range of [-1,1], where 0 is the neutral
+  // position of the control. Alwasy 0 if the device does not support it.

[mustaq, 2017/01/03 19:09:24]

Please also add "(or barrel pressure)" in the first line. "Barrel" seems more
intuitive to me.

Also a nit: s/Alwasy/Always/.

[lanwei, 2017/01/05 16:13:41]

Done.

+  float tangentialPressure;
+
+  // The clockwise rotation of a pen stylus around its own major axis, in
+  // degrees of a range of [0,359]). Alwasy 0 if the device does not support

[mustaq, 2017/01/03 19:09:24]

Nit: "in degrees in the range [0,359]."

[lanwei, 2017/01/05 16:13:41]

Done.

+  // it.
+  int twist;
+
   Button button;
   PointerType pointerType;
 };