Fix vector resize logic when encoding non-BMP chars to x-user-defined

Fix vector resize logic when encoding non-BMP chars to x-user-defined

Since non-BMP characters take two UChars, when encoding to
x-user-defined with replacement characters ('?') may result the output
being shorter than the input. The encoding logic assumed the
replacement would always be larger, and vectors don't like being
shrunk. Correct the logic and make it more readable, add tests.

BUG=661823
Committed: https://crrev.com/38d521c4ccc88c44de1d189c82b895c4a39f90c4
Cr-Commit-Position: refs/heads/master@{#429964}

[jsbell, 2016-11-03 00:05:21]

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

[commit-bot: I haz the power, 2016-11-03 00:05:54]

Dry run: 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, 2016-11-03 00:09:47]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-03 00:09:48]

Dry run: Try jobs failed on following builders:
  ios-device on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-device/builds...)
  ios-simulator on master.tryserver.chromium.mac (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.mac/builders/ios-simulator/bui...)

[jsbell, 2016-11-03 00:14:14]

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

[commit-bot: I haz the power, 2016-11-03 00:14:44]

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

[jsbell, 2016-11-03 00:15:28]

jsbell@chromium.org changed reviewers:
+ tkent@chromium.org

[jsbell, 2016-11-03 00:15:29]

tkent@ - please take a look? (mostly the same as the upstream patch)

[commit-bot: I haz the power, 2016-11-03 02:21:16]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-03 02:21:17]

Dry run: Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[tkent, 2016-11-03 12:14:25]

lgtm

[jsbell, 2016-11-03 16:34:30]

The CQ bit was checked by jsbell@chromium.org

[commit-bot: I haz the power, 2016-11-03 16:35:27]

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, 2016-11-03 21:34:39]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-03 21:34:40]

Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[jsbell, 2016-11-03 21:44:02]

The CQ bit was checked by jsbell@chromium.org

[commit-bot: I haz the power, 2016-11-03 21:44:58]

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, 2016-11-04 01:49:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-11-04 01:49:45]

Try jobs failed on following builders:
  win_chromium_rel_ng on master.tryserver.chromium.win (JOB_FAILED,
http://build.chromium.org/p/tryserver.chromium.win/builders/win_chromium_rel_...)

[jsbell, 2016-11-04 17:04:57]

The CQ bit was checked by jsbell@chromium.org

[commit-bot: I haz the power, 2016-11-04 17:05:43]

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, 2016-11-04 18:58:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2016-11-04 19:18:38]

Description was changed from

==========
Fix vector resize logic when encoding non-BMP chars to x-user-defined

Since non-BMP characters take two UChars, when encoding to
x-user-defined with replacement characters ('?') may result the output
being shorter than the input. The encoding logic assumed the
replacement would always be larger, and vectors don't like being
shrunk. Correct the logic and make it more readable, add tests.

BUG=661823
==========

to

==========
Fix vector resize logic when encoding non-BMP chars to x-user-defined

Since non-BMP characters take two UChars, when encoding to
x-user-defined with replacement characters ('?') may result the output
being shorter than the input. The encoding logic assumed the
replacement would always be larger, and vectors don't like being
shrunk. Correct the logic and make it more readable, add tests.

BUG=661823

Committed: https://crrev.com/38d521c4ccc88c44de1d189c82b895c4a39f90c4
Cr-Commit-Position: refs/heads/master@{#429964}
==========

[commit-bot: I haz the power, 2016-11-04 19:18:39]

Patchset 2 (id:??) landed as
https://crrev.com/38d521c4ccc88c44de1d189c82b895c4a39f90c4
Cr-Commit-Position: refs/heads/master@{#429964}