Added experimental tilt and tiltDirection to the Touch interface

public/web/WebTouchPoint.h

Index: public/web/WebTouchPoint.h
diff --git a/public/web/WebTouchPoint.h b/public/web/WebTouchPoint.h
index fc0231a5cab40a187d777ce808c233115d16969b..8b4bc72bbd3ebf7ee086548335afa13c9c27552f 100644
--- a/public/web/WebTouchPoint.h
+++ b/public/web/WebTouchPoint.h
@@ -33,6 +33,7 @@
 
 #include "../platform/WebCommon.h"
 #include "../platform/WebFloatPoint.h"
+#include <limits>
 
 namespace blink {
 
@@ -45,6 +46,8 @@ public:
         , radiusY(0)
         , rotationAngle(0)
         , force(0)
+        , tilt(std::numeric_limits<float>::quiet_NaN())
+        , tiltDirection(std::numeric_limits<float>::quiet_NaN())
     {
     }
 
@@ -66,6 +69,8 @@ public:
     float radiusY;
     float rotationAngle;
     float force;
+    float tilt;
+    float tiltDirection;
 };
 
 } // namespace blink