Bug 1013570 - [B2G][Keyboard]Double or triple tapping on the spacebar
can result in 2-3 periods, as well as deleted characters.
 - Send the next key after the previous sendKey is resolved.
Merge pull request #19856 from RudyLu/keyboard/Bug1013570_commit

Bug 1013570 - [B2G][Keyboard]Double or triple tapping on the spacebar.
r=timdream.