Fix caret invalidation when a block is removed

Fix caret invalidation when a block is removed

Clear previous and/or current block when a block is being removed.

BUG=701267
Review-Url: https://codereview.chromium.org/2754993002
Cr-Commit-Position: refs/heads/master@{#457597}
Committed: https://chromium.googlesource.com/chromium/src/+/eeaca73ad3f97a71c35c8298ccf691ebad35161d

[Xianzhu, 2017-03-16 21:08:56]

The CQ bit was checked by wangxianzhu@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2017-03-16 21:09:40]

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

[Xianzhu, 2017-03-16 21:11:12]

wangxianzhu@chromium.org changed reviewers:
+ chrishtr@chromium.org

[Xianzhu, 2017-03-16 21:11:13]

Sorry for the bugs of caret paint invalidation. This bug is really a result of
my carelessness when creating the first version.

[chrishtr, 2017-03-16 21:28:05]

lgtm

[Xianzhu, 2017-03-16 21:47:36]

The CQ bit was unchecked by wangxianzhu@chromium.org

[Xianzhu, 2017-03-16 21:47:39]

The CQ bit was checked by wangxianzhu@chromium.org

[commit-bot: I haz the power, 2017-03-16 21:48:14]

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, 2017-03-16 23:07:12]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1489700859792870, "parent_rev":
"2ca42b225daf7f14d092d601f67b154fcc3b8876", "commit_rev":
"eeaca73ad3f97a71c35c8298ccf691ebad35161d"}

[commit-bot: I haz the power, 2017-03-16 23:08:03]

Description was changed from

==========
Fix caret invalidation when a block is removed

Clear previous and/or current block when a block is being removed.

BUG=701267
==========

to

==========
Fix caret invalidation when a block is removed

Clear previous and/or current block when a block is being removed.

BUG=701267

Review-Url: https://codereview.chromium.org/2754993002
Cr-Commit-Position: refs/heads/master@{#457597}
Committed:
https://chromium.googlesource.com/chromium/src/+/eeaca73ad3f97a71c35c8298ccf6...
==========

[commit-bot: I haz the power, 2017-03-16 23:08:05]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/chromium/src/+/eeaca73ad3f97a71c35c8298ccf6...