[OT-PW] Pass properties to build PaintWorkletStylePropertyMap

Right now in the CSSPaintValue::GetImage, we are using empty native and
custom properties to build the PaintWorkletStylePropertyMap, and this is
because the DocumentPaintDefinitionMap was not ready yet for the
off-thread paint worklet.

Now that the DocumentPaintDefinition has been implemented, we can pass
the actual properties to build the style map. This CL does that.

Bug: 946519
Change-Id: If8fb1da383f2590ceffa0f3dcda66e380e937051
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1584559
Commit-Queue: Xida Chen <xidachen@chromium.org>
Reviewed-by: Stephen McGruer <smcgruer@chromium.org>
Reviewed-by: Jeremy Roman <jbroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#657302}
12 files changed