Batched implementation of drawLattice() for GPU

Bechmarks (Nexus 6P):

Src=100x100, Dst=250x250, NumRects=9
Android              77.7us
Skia (without patch) 57.2us
Skia (with patch)    30.9us

Src=100x100, Dst=500x500, NumRects=9
Android              77.0us
Skia (without patch) 56.9us
Skia (with patch)    31.8us

Src=100x100, Dst=1000x1000, NumRects=9
Android              180us
Skia (without patch) 96.8us
Skia (with patch)    70.5us

Src=100x100, Dst=250x250, NumRects=15
Android              208us
Skia (without patch) 155us
Skia (with patch)    38.2us

Src=100x100, Dst=500x500, NumRects=15
Android              207us
Skia (without patch) 152us
Skia (with patch)    38.4us

Src=100x100, Dst=1000x1000, NumRects=15
Android              233us
Skia (without patch) 156us
Skia (with patch)    99.9us

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2255963002

Committed: https://skia.googlesource.com/skia/+/93242c4ae50dfcc0d922cdb3ba80bbc7b4bbe93d
Review-Url: https://codereview.chromium.org/2255963002
10 files changed