This issue was introduced by I22ce0e9eadc941f84e3a9b23462f194e51dd7180.
Need to decrement the two utf16 chars in KEYCAP handling.
To add unit tests, this CL also addresses the Bug: 24184208 by
introducing self built fonts since there is no good example in system
installed fonts.
Bug: 24184208
Change-Id: I23fa008adbaced78a3cb96442a6bc8892ab84ce8