Roll engine f38f6a09be65..79f898e61d9c (5 commits) (#49264)

https://github.com/flutter/engine/compare/f38f6a09be65...79f898e61d9c

git log f38f6a09be65..79f898e61d9c --first-parent --oneline
2020-01-21 ferhat@gmail.com Fix RRect hittest optimization to handle malformed corner radius (flutter/engine#15859)
2020-01-21 nathanrogers@google.com Add size parameters to Vulkan surface functions (flutter/engine#15748)
2020-01-21 54371434+godofredoc@users.noreply.github.com Add .vpython dependencies to migrate run_tests.py to vpython. (flutter/engine#15161)
2020-01-21 nathanrogers@google.com [fuchsia] Support Skia tracing arguments (flutter/engine#15745)
2020-01-21 skia-flutter-autoroll@skia.org Roll src/third_party/skia 215c34be2bd3..cedab522227a (9 commits) (flutter/engine#15856)


If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-engine-flutter-autoroll
Please CC aaclarke@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

bin/internal/engine.version

-f38f6a09be654dfc431c66f8a88383febbf33ff6
+79f898e61d9ca8fc7dbcf15378c5299993dcfd36