Have draw(Text|PosText|PosTextH) use a single entry on the device

Handle the positioning of drawText at the canvas layer. Simplify
the code by removing similar implementations.

Change-Id: I8b711783435072f560e29fca1dd934fa2e345ed2
Reviewed-on: https://skia-review.googlesource.com/127131
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
29 files changed