Change web platform test with mouse inputs under "pinterevents/"

Use test_driver Actions class in the web platform tests with mouse
inputs in "pinterevents/" to simulate mouse inputs to make the tests
pass on wpt serve.

Bug: 606367
Change-Id: I2f00c3195fafb8bc600250631106cd9eabe79b90
Reviewed-on: https://chromium-review.googlesource.com/c/1383330
Commit-Queue: Lan Wei <lanwei@chromium.org>
Reviewed-by: Navid Zolghadr <nzolghadr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#619697}
31 files changed