SkBlitter_RGB16: Add device-specific optimization hooks
SkBlitter_RGB16: Add device-specific optimization hooks

Change-Id: I18bf4825669fef6fcc10e5d48271e7ea9abb3ed6
(cherry picked from commit 5d5e3dd98e15a5d25fcddf41f00dc5989942d094)
(cherry picked from commit afbd633b035a8b8f6017f52f6ad398a076aee841)
(cherry picked from commit 814fe785689f0b018283fbc2b02a2d230f0221cb)

StelixROM/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia,marlontoe/android_external_skia,StelixROM/android_external_skia,marlontoe/android_external_skia