18945 Add ui_benchmarks (affects: tests, cla: yes, perf: speed, severe: performance, waiting for tree to go green)

perf: speed - 13 pull request(s)

17175 Enhance image_filter_layer caching to filter a cached child (cla: yes, perf: speed, severe: performance, waiting for tree to go green)

17601 Read SkSLs from asset (cla: yes, perf: speed, severe: performance)

17621 Optimize static content scrolling (cla: yes, perf: speed, severe: performance)

17753 [fuchsia] Enable raster cache on Fuchsia (cla: yes, perf: speed, severe: performance)

17866 [web] Speedup color to css string 25% (cla: yes, perf: speed)