Changed Blimp IME to use PopUp
Blimp IME currently shows an EditText on the top of the soft keyboard.
This CL changes it to use a popup instead based on an AlertDialog.
WebInputBox was renamed to ImeHelperDialog which contains an ImeEditText.
This change also fixes the issue of view resize due to IME.
BUG=
611111
Committed:
https://crrev.com/10a8e63afa2ca6e91671293fa6c2781c32ea1162
Cr-Commit-Position: refs/heads/master@{#415819}