Fire pointerup/down events for corresponding mouse events.

Includes tests for pointerup/down event properties and for prevent
default behavior.

Also fixed a crack in eventSender that kept MouseEvent buttons unset.

BUG=476571,541311

Review URL: https://codereview.chromium.org/1391393002

Cr-Commit-Position: refs/heads/master@{#356339}
diff --git a/third_party/WebKit/LayoutTests/TestExpectations b/third_party/WebKit/LayoutTests/TestExpectations
index e46f421..2aaf440 100644
--- a/third_party/WebKit/LayoutTests/TestExpectations
+++ b/third_party/WebKit/LayoutTests/TestExpectations
@@ -185,6 +185,7 @@
 crbug.com/445100 fast/block/float/marquee-shrink-to-avoid-floats.html [ Failure Pass ]
 crbug.com/469657 fast/events/mouse-event-buttons-attribute.html [ Failure Pass ]
 crbug.com/469657 virtual/pointerevent/fast/events/mouse-event-buttons-attribute.html [ Failure Pass ]
+crbug.com/548226 [ Win ] virtual/pointerevent/fast/events/pointerevents/mouse-pointer-event-properties.html [ Failure Pass ]
 crbug.com/432129 fast/html/marquee-scroll.html [ Failure Pass ]
 crbug.com/320139 fast/repaint/block-layout-inline-children-replaced.html [ Failure Pass ]
 crbug.com/320139 virtual/syncpaint/fast/repaint/block-layout-inline-children-replaced.html [ Skip ]