Exception might be thrown when trying to show AlertDialog on IME context on certain devices

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Install Mozc 2.16.2000.103 into Sony Xperia Z3 (Android 4.4.4)
2. Long tap the Hiragana/Alphabet key at bottom left to show an AlertDialog

What is the expected output?
Mozc shouldn't crash at least.

What do you see instead?
Mozc process is terminated due to an uncaught exception.

Please use labels and text to provide additional information.
Showing AlertDialog triggers this issue in practice.  Originally reported as
- https://productforums.google.com/forum/#!topic/ime-ja/uiZPk_6Nn4g
- Issue 256

Also happens when showing the warning dialog on symbol picker (for carrier 
emoji).

Original issue reported on code.google.com by yukawa@google.com on 19 Dec 2014 at 6:45

[GoogleCodeExporter]

This issue was closed by revision r461.

Original comment by yukawa@google.com on 19 Dec 2014 at 6:50

• Changed state: Fixed

[GoogleCodeExporter]

Issue 256 has been merged into this issue.

Original comment by yukawa@google.com on 19 Dec 2014 at 6:51

[GoogleCodeExporter]

Sorry, r461 caused some compile errors.  I'll fix it shortly.

Original comment by yukawa@google.com on 21 Dec 2014 at 2:14

• Changed state: Started

[GoogleCodeExporter]

This issue was closed by revision r462.

Original comment by yukawa@google.com on 21 Dec 2014 at 2:17

• Changed state: Fixed

[GoogleCodeExporter]

Issue 256 has been merged into this issue.

Original comment by yukawa@google.com on 21 Dec 2014 at 2:18