Pass MotionEvent tool type to Blink.
This maps MotionEvent tool type to PointerEvent pointerType and passes
that to WebTouchPoints.
This CL is a part of a patch series:
1. https://codereview.chromium.org/
1253183005/
for new WebPointerProperties fields
2. https://codereview.chromium.org/
1260693003/
for eventSender web pointer property support
3. https://codereview.chromium.org/
1192463008/
for handling pointer type in Blink event handlers
4. https://codereview.chromium.org/
1190013002/ (this)
BUG=514360
Review URL: https://codereview.chromium.org/
1190013002
Cr-Commit-Position: refs/heads/master@{#342992}