Hook up CSSPaintValue::image to CSS Paint API callback.
This introduces the plumbing required for custom paint.
PaintGeneratedImage - Holds onto a SkPicture for painting. This is
produced as the result of custom paint.
CSSPaintImageGeneratorImpl - Generates a PaintGeneratedImage based on a
LayoutObject and size. Invokes the custom paint callback inside
CSSPaintDefinition.
BUG=578252
Review URL: https://codereview.chromium.org/1866623002
Cr-Commit-Position: refs/heads/master@{#389838}
63 files changed