[ElementVisibilityObserver] Fix regression with default threshold

[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839
Review-Url: https://codereview.chromium.org/2919543002
Cr-Original-Commit-Position: refs/heads/master@{#476265}
Review-Url: https://codereview.chromium.org/2920863003 .
Cr-Commit-Position: refs/branch-heads/3112@{#120}
Cr-Branched-From: b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed: https://chromium.googlesource.com/chromium/src/+/848e7b224a1b681fe3154f3b5f6fe2054d285c5b

[johnme, 2017-06-02 17:03:49]

Description was changed from

==========
[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839

Review-Url: https://codereview.chromium.org/2919543002
Cr-Commit-Position: refs/heads/master@{#476265}
(cherry picked from commit 945f4bf50cac68aee482fa5165c3a43379ed2241)
==========

to

==========
[ElementVisibilityObserver] Fix regression with default threshold

https://codereview.chromium.org/2830713003 (r468137,
913ee5fe4cfcc42ebc568965169258bc37fb0237) changed the default threshold
of ElementVisibilityObserver from std::numeric_limits<float>::min() to
zero, assuming that they would behave the same.

It turns out that there's some confusion here - see
https://github.com/WICG/IntersectionObserver/issues/164 - and for now
we should continue to use std::numeric_limits<float>::min() to
distinguish between completely hidden and partially visible.

BUG=726839

Review-Url: https://codereview.chromium.org/2919543002
Cr-Original-Commit-Position: refs/heads/master@{#476265}
Review-Url: https://codereview.chromium.org/2920863003 .
Cr-Commit-Position: refs/branch-heads/3112@{#120}
Cr-Branched-From:
b6460e24cf59f429d69de255538d0fc7a425ccf9-refs/heads/master@{#474897}
Committed:
https://chromium.googlesource.com/chromium/src/+/848e7b224a1b681fe3154f3b5f6f...
==========

[johnme, 2017-06-02 17:03:51]

Committed patchset #1 (id:1) manually as
848e7b224a1b681fe3154f3b5f6fe2054d285c5b.