Improve usage of window rectangles
* Skips non-AA diff rect elements and replaces them with window
rectangles.
* Places window rectangles in the interiors of antialiased diff rects.
* Arranges two overlapping window rectangles in a plus shape inside of
diff rounded rects.
* Enables window rectangles when clearing and generating clip masks.
GTX 960 perf result (with vs. without window rectangles):
glinst4 msaa16 gpu
keymobi_pinterest.skp 0.48 -> 0.17 [ 35%] 2.77 -> 1.49 [ 54%] 0.22 -> 0.16 [ 70%]
keymobi_digg_com.skp 0.42 -> 0.23 [ 55%] 2.34 -> 1.08 [ 46%] 0.25 -> 0.21 [ 83%]
desk_jsfiddlebigcar.skp 0.28 -> 0.16 [ 59%] 1.70 -> 0.96 [ 57%] 0.19 -> 0.14 [ 70%]
top25desk_wordpress.skp 0.45 -> 0.18 [ 40%] 2.78 -> 1.53 [ 55%] 0.21 -> 0.19 [ 94%]
top25desk_weather_com.skp 2.01 -> 1.93 [ 96%] 23.5 -> 2.54 [ 11%] 1.90 -> 1.68 [ 88%]
keymobi_blogger.skp 0.57 -> 0.37 [ 65%] 2.87 -> 1.54 [ 54%] 0.43 -> 0.33 [ 77%]
keymobi_linkedin.skp 0.32 -> 0.17 [ 51%] 1.93 -> 1.04 [ 54%] 0.17 -> 0.15 [ 91%]
keymobi_bing_com_search_... 0.29 -> 0.25 [ 83%] 1.85 -> 1.23 [ 66%] 0.50 -> 0.24 [ 48%]
keymobi_theverge_com_201... 1.00 -> 0.67 [ 68%] 9.46 -> 3.84 [ 41%] 0.72 -> 0.65 [ 90%]
keymobi_sfgate_com_.skp 1.56 -> 1.13 [ 72%] 4.49 -> 2.86 [ 64%] 1.54 -> 1.11 [ 72%]
...
GEOMEAN (All 79 blink skps) 1.04 -> 0.90 [ 86%] 4.22 -> 2.81 [ 67%] 0.95 -> 0.89 [ 94%]
BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=2289363005
Committed: https://skia.googlesource.com/skia/+/db42be9a326c747ff92ed1da8c3536c5b3e8e22b
Review-Url: https://codereview.chromium.org/2289363005
25 files changed