Fixes https://github.com/flutter/flutter/issues/52356

Fix for https://github.com/flutter/flutter/issues/51978 to use the bounds of the filtered result as the layer's paint bounds.

* Canvas: Remove some unused virtuals, and prepare for signature change

* Better vertices fix

* Add empty placeholders for old signature

https://skia.googlesource.com/skia.git/+log/75e29072e7d6..f9329afa27a0

git log 75e29072e7d6..f9329afa27a0 --date=short --first-parent --format='%ad %ae %s'
2020-03-13 jvanverth@google.com Revert "Clear out atlases if they haven't been used in a while."
2020-03-13 csmartdalton@google.com Remove instanced draws and simplify GrMesh
2020-03-13 reed@google.com remove legacy virtual from enforcer
2020-03-13 jvanverth@google.com Clear out atlases if they haven't been used in a while.

Created with:
  gclient setdep -r src/third_party/skia@f9329afa27a0

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: brianosman@google.com

https://skia.googlesource.com/skia.git/+log/ba96256581c2..75e29072e7d6

git log ba96256581c2..75e29072e7d6 --date=short --first-parent --format='%ad %ae %s'
2020-03-13 bryct@amazon.com Implement support for path effects in SkSVGDevice backend.
2020-03-13 robertphillips@google.com Make AAFlatteningConvexPathOp surface its programInfos at record time

Created with:
  gclient setdep -r src/third_party/skia@75e29072e7d6

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: brianosman@google.com

Fuchsia benchmarks depend the name being precisely "vsync callback".
Since this is causing immediate build issues, change it back to "vsync
callback" on Fuchsia.  Stronger testing for this in the long run is
currently under discussion.

b/150902962

https://skia.googlesource.com/skia.git/+log/f0140ee00f95..1743144ab839

git log f0140ee00f95..1743144ab839 --date=short --first-parent --format='%ad %ae %s'
2020-03-12 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 16ae92a4ee52..7e857092052e (6 commits)
2020-03-11 jvanverth@google.com Remove need for gpu when unrefing managed resources.

Created with:
  gclient setdep -r src/third_party/skia@1743144ab839

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/skia-flutter-autoroll
Please CC brianosman@google.com on the revert to ensure that a human
is aware of the problem.

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+/master/autoroll/README.md

Bug: None
Tbr: brianosman@google.com