Adjust visual overflow rect for rounded/shifted ascent/descent

Adjust visual overflow rect for rounded/shifted ascent/descent

For now we round and/or shift ascent and descent to integers in some cases,
and we may layout using ascent/descent smaller than the original, causing that
painted text at the laid-out position may overflow the visual overflow
calculated based on layout geometries.

Now record the loss in FontMetrics and adjust visual overflow rect to cover
the overflows.

BUG=706298
TBR=wangxianzhu@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2803483002
Cr-Original-Commit-Position: refs/heads/master@{#464689}
Review-Url: https://codereview.chromium.org/2816243004
Cr-Commit-Position: refs/branch-heads/3071@{#5}
Cr-Branched-From: a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed: https://chromium.googlesource.com/chromium/src/+/40094f47127ab282c4eef8f62bfdd2b92a31cbb4

[Xianzhu, 2017-04-14 23:41:24]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2017-04-14 23:41:57]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2017-04-14 23:50:28]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1492213284748540, "parent_rev":
"acf6dff9fb59299ac7bdf99f754f5b56f6300c80", "commit_rev":
"40094f47127ab282c4eef8f62bfdd2b92a31cbb4"}

[commit-bot: I haz the power, 2017-04-14 23:51:19]

Description was changed from

==========
Adjust visual overflow rect for rounded/shifted ascent/descent

For now we round and/or shift ascent and descent to integers in some cases,
and we may layout using ascent/descent smaller than the original, causing that
painted text at the laid-out position may overflow the visual overflow
calculated based on layout geometries.

Now record the loss in FontMetrics and adjust visual overflow rect to cover
the overflows.

BUG=706298
TBR=wangxianzhu@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2803483002
Cr-Commit-Position: refs/heads/master@{#464689}
==========

to

==========
Adjust visual overflow rect for rounded/shifted ascent/descent

For now we round and/or shift ascent and descent to integers in some cases,
and we may layout using ascent/descent smaller than the original, causing that
painted text at the laid-out position may overflow the visual overflow
calculated based on layout geometries.

Now record the loss in FontMetrics and adjust visual overflow rect to cover
the overflows.

BUG=706298
TBR=wangxianzhu@chromium.org
NOTRY=true
NOPRESUBMIT=true

Review-Url: https://codereview.chromium.org/2803483002
Cr-Original-Commit-Position: refs/heads/master@{#464689}
Review-Url: https://codereview.chromium.org/2816243004
Cr-Commit-Position: refs/branch-heads/3071@{#5}
Cr-Branched-From:
a106f0abbf69dad349d4aaf4bcc4f5d376dd2377-refs/heads/master@{#464641}
Committed:
https://chromium.googlesource.com/chromium/src/+/40094f47127ab282c4eef8f62bfd...
==========

[commit-bot: I haz the power, 2017-04-14 23:51:21]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/40094f47127ab282c4eef8f62bfd...