Revert "Move the modifier variable from NativePixmapPlane to NativePixmapHandle"

This reverts commit 6f1b99ba183a4046e4915b77741da288b043c59f.

Reason of the revert:
With this CL, Chrome on R76-12184.0.0 (eve) crashes when an ARC++ app is launched.

TBR=sandersd@chromium.org,dcastagna@chromium.org,dcheng@chromium.org,rjkroege@chromium.org
BUG=957381
TEST=R76-12184.0.0 (eve) works with this revert

Change-Id: I1d833880611b4d3d1c03e074ccfcb8db12d7acd0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1600792
Auto-Submit: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Hirokazu Honda <hiroh@chromium.org>
Commit-Queue: Hirokazu Honda <hiroh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657569}
19 files changed