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Users report touchpad sometime stop working. But it can not reproduce on our
side. I suspected the issue maybe:

1. Direct Manipulation failed at initialize
2. Direct Manipulation on incorrect state similar to issue 847611
3. Chrome does not cover some state transition for Direct Manipulation

In this patch, we add logs behind feature flag PrecisionTouchpadLogging to
help us debug. We use feature flag instead of VLOG because VLOG is not working
on Windows (issue 440172).

Bug: 914914
Change-Id: I02a28418914f18558667666f9e0779cb8d4d2eb7
Reviewed-on: https://chromium-review.googlesource.com/c/1450612
Commit-Queue: Jianpeng Chao <chaopeng@chromium.org>
Reviewed-by: Bruce Dawson <brucedawson@chromium.org>
Reviewed-by: Scott Violet <sky@chromium.org>
Cr-Commit-Position: refs/heads/master@{#629786}