[Author: thomasvl]
[Author: thomasvl]

NSEvent throws if you call -characters on a non key event, so instead of
  checking the requested mask, we have to check the event type (say someone
  uses any event as the mask, and it's a click event...)
Also handle keydown or up for the tab check.

R=dmaclach,stuartmorgan
DELTA=8  (1 added, 0 deleted, 7 changed)
isongga/google-toolbox-for-mac,isongga/google-toolbox-for-mac,isongga/google-toolbox-for-mac