6bddf99dc0
Do not eagerly create an `SkPaint` object that's strongly referenced by `CkPaint`. Instead, when a `Canvas.draw*` is called, create a temporary `SkPaint` object, pass it to Skia, then immediately delete it. This way there are no persistent `SkPaint` handles lurking in the system that transitively hold onto expensive native resources. Addresses the `Paint` issue in https://github.com/flutter/flutter/issues/153678 in CanvasKit Spot checking some benchmarks. Here's the effect of this PR on `draw_rect_variable_paint`. It's a bit of a stress test as it creates 300K distinct `Paint` objects to render 600 pictures (a typical ratio does not normally exceed ten paints to one picture). Even so, the effect of creating an extra `SkPaint` on every `draw*` command does not look significant. However, removing a dependency on the GC for 300K objects looks like a good trade-off. ## Before Allocation stats: ``` Paint Created: 300000 Paint Deleted: 300000 Paint Leaked: 300000 Picture Created: 600 Picture Deleted: 599 Picture Leaked: 599 ``` Performance stats: ``` windowRenderDuration: (samples: 98 clean/2 outliers/100 measured/300 total) | average: 4679.551020408163 μs | outlier average: 5100 μs | outlier/clean ratio: 1.0898481452084188x | noise: 3.11% sceneBuildDuration: (samples: 98 clean/2 outliers/100 measured/300 total) | average: 4689.765306122449 μs | outlier average: 5100 μs | outlier/clean ratio: 1.087474461321549x | noise: 3.19% drawFrameDuration: (samples: 97 clean/3 outliers/100 measured/300 total) | average: 8447.474226804125 μs | outlier average: 9332.666666666666 μs | outlier/clean ratio: 1.1047878236850721x | noise: 3.52% ``` ## After Allocation stats: ``` Picture Created: 600 Picture Deleted: 599 Picture Leaked: 599 ``` Performance stats: ``` windowRenderDuration: (samples: 97 clean/3 outliers/100 measured/300 total) | average: 4780.40206185567 μs | outlier average: 5133.666666666667 μs | outlier/clean ratio: 1.0738985131877936x | noise: 2.70% sceneBuildDuration: (samples: 97 clean/3 outliers/100 measured/300 total) | average: 4787.6082474226805 μs | outlier average: 5133.666666666667 μs | outlier/clean ratio: 1.0722821085936345x | noise: 2.72% drawFrameDuration: (samples: 97 clean/3 outliers/100 measured/300 total) | average: 8243.309278350516 μs | outlier average: 9033.333333333334 μs | outlier/clean ratio: 1.0958382159768851x | noise: 2.60% ```