Add maxTouchPoints for pointer events

Source/core/page/Settings.in

 # Defines properties which are available on the Settings object.
 #
 # Please think carefully before adding a new Setting.  Some questions to
 # consider are:
 # - Should this be a RuntimeEnabledFeature instead? Settings are for things
 #   which we support either values of at runtime.  Features are set at renderer
 #   process startup and are never changed. Features also tend to be set to a
 #   value based on the platform or the stability of the code in question, where
 #   as settings both codepaths need to be stable.
 # - How will you ensure test coverage of all relevant values of your setting?
@@ skipping 137 matching lines @@
 
 # Limited use by features which behave differently depending on the input
 # devices available.  For example, the pointer and hover media queries.
 # Note that we need to be careful when basing behavior or UI on this -
 # just because a device is present doesn't mean the user cares about it
 # or uses it (i.e. Chromebook Pixel users generally don't want to give up
 # screen real estate just because they happen to have a touchscreen).
 deviceSupportsTouch initial=false
 deviceSupportsMouse initial=true
 
+# This value indicates the number of simultaneous multi-touch points supported
+# by the currently connected screen/digitizer that supports the most points.
+# From Pointer Events spec:
+#   http://www.w3.org/TR/pointerevents/#widl-Navigator-maxTouchPoints
+maxTouchPoints type=int, initial=0
+
 # Whether touch gestures should be "fuzzed" to nearest touch targets.
 # It's expected that this is enabled everywhere by default, but it may be
 # disabled for testing purposes as the algorithm is not yet perfect.
 # crbug.com/304895 tracks removal once we're satisfied with the algorithm.
 touchAdjustmentEnabled initial=true
 
 # A mostly-stable performance optimization. crbug.com/304518 tracks removal.
 compositorTouchHitTesting initial=true
 
 fixedPositionCreatesStackingContext initial=false
@@ skipping 59 matching lines @@
 # Settings for experimental desktop pinch-zoom support (with semantics
 # optimized for large screens).  Pinch-zoom generally is implemented mainly
 # outside of blink (in the compositor) and doesn't require any settings.
 # These settings are for an experimental modification to how pinch-zoom
 # behaves.  TODO(wjmaclean): link to design document.
 # crbug.com/304869 tracks removal.
 pinchVirtualViewportEnabled initial=false
 useSolidColorScrollbars initial=false
 
 mainFrameClipsContent initial=true