Add WebPointerProperties type.

public/web/WebTouchPoint.h

Index: public/web/WebTouchPoint.h
diff --git a/public/web/WebTouchPoint.h b/public/web/WebTouchPoint.h
index fc0231a5cab40a187d777ce808c233115d16969b..3386e18151100c6065f9a973241fa521d653a533 100644
--- a/public/web/WebTouchPoint.h
+++ b/public/web/WebTouchPoint.h
@@ -33,18 +33,20 @@
 
 #include "../platform/WebCommon.h"
 #include "../platform/WebFloatPoint.h"
+#include "WebMouseProperties.h"
+#include "WebPointerProperties.h"
 
 namespace blink {
 
-class WebTouchPoint {
+// TODO(e_hakkinen): Replace WebTouchEvent with WebPointerEvent and remove
+//                   WebTouchEvent and this.
+class WebTouchPoint : public WebMouseProperties, public WebPointerProperties {

[Rick Byers, 2015/07/06 17:22:38]

I was originally thinking we'd use aggregation (i.e. a "pointerProperties field)
instead of inheritance since the use of multiple inheritance is a little
unusual.

But I like the idea of using inheritance to minimize the changes necessary to
the code.  As long as we're careful it should be fine.

 public:
     WebTouchPoint()
-        : id(0)
+        : WebMouseProperties()
+        , WebPointerProperties()
         , state(StateUndefined)
-        , radiusX(0)
-        , radiusY(0)
         , rotationAngle(0)
-        , force(0)
     {
     }
 
@@ -57,15 +59,11 @@ public:
         StateCancelled,
     };
 
-    int id;
     State state;
     WebFloatPoint screenPosition;
     WebFloatPoint position;

[Rick Byers, 2015/07/06 17:22:39]

These co-ordinate properties could eventually be moved into WebPointerProperties
too.  Don't try to do that here - there is some complexity (eg. point vs.
separate x/y members, floats vs. ints) but I don't expect it would be that hard
to do in a later CL.  Maybe add a TODO saying they should move?

[USE eero AT chromium.org, 2015/07/07 10:00:56]

Done.

 
-    float radiusX;
-    float radiusY;

[Rick Byers, 2015/07/06 17:22:39]

You can't just replace radiusX/radiusY with width/height - they have different
semantics in the case of rotation.  For now why not just keep them called
radiusX/radiusY?

In fact, it might be simplest if the first CL doesn't change the name of ANY
fields, then we don't need to change chromium at all.  We can always do specific
renames later if we want to change semantics, but it's not clear to me when
we'll actually need that.

[USE eero AT chromium.org, 2015/07/07 10:00:56]

Done.

     float rotationAngle;
-    float force;
 };
 
 } // namespace blink