This adds CatmullRomCurve animation curve, and a CatmullRomSpline, which is what it uses to do interpolation.

This allows us to create animation curves which can smoothly interpolate the values given to the curve.

Since I've introduced a 2D spline curve, I also created a Curve2D base class for such parametric curves.

https://github.com/flutter/engine/compare/3f52888b3bcf...a50f1ef56a05

git log 3f52888b3bcf..a50f1ef56a05 --first-parent --oneline
2020-01-08 gw280@google.com Migrate flutter_runner from flutter_runner::{Thread,Loop} to fml::{Thread,MessageLoop} (flutter/engine#15118)
2020-01-07 ferhat@gmail.com Refactor BitmapCanvas, lazily allocate canvas, fix image composition bug. (flutter/engine#15153)
2020-01-07 ferhat@gmail.com Recover when browser throws on ImageElement.decode due to too many images (flutter/engine#15160)
2020-01-07 garyq@google.com Fix RectHeightStyle::kMax ascent computation bug (flutter/engine#15106)


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 garyq@google.com on the revert to ensure that a human
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To report a problem with the AutoRoller itself, please file a bug:
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This is follow-up to https://github.com/flutter/flutter/commit/ee7a37f1d3f12ca815d755a557f16765942897a4.

Revert "Document reasoning for why CustomMultiChildLayout size can't depend on children and how to do it (#47797)" (#48369)

This reverts commit de2514c0 as it breaks analyze-linux and web_tests-0-linux checks.

https://github.com/flutter/engine/compare/3851981b863a...3f52888b3bcf

git log 3851981b863a..3f52888b3bcf --first-parent --oneline
2020-01-07 skia-flutter-autoroll@skia.org Roll src/third_party/skia d445e2b6fcf1..91e0d7526944 (44 commits) (flutter/engine#15232)
2020-01-07 dnfield@google.com Font subset (flutter/engine#14828)
2020-01-06 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/linux-amd64 from MwGkB... to xYmDF... (flutter/engine#15145)
2020-01-06 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from Kom_K... to nbeLe... (flutter/engine#15149)
2020-01-06 skia-flutter-autoroll@skia.org Roll src/third_party/skia 6791ee2f8059..d445e2b6fcf1 (1 commits) (flutter/engine#15148)
2020-01-06 skia-flutter-autoroll@skia.org Roll src/third_party/dart 76e3faa9824e..bebc7d3af5bd (1 commits) (flutter/engine#15146)
2020-01-04 skia-flutter-autoroll@skia.org Roll src/third_party/dart 2f57602411b3..76e3faa9824e (37 commits) (flutter/engine#15143)


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 garyq@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:
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Document reasoning for why CustomMultiChildLayout size can't depend on children and how to do it (#47797)

This reverts commit 866fa64d.

* Reword flutter run help screen.

* As per Hixie request, added Efthymios Sarmpanis to the AUTHORS file

* fix test
Co-authored-by: Efthymis Sarmpanis <e.sarbanis@gmail.com>

recomputing the path context in the getter violates flutter repo style guide and adds a small but measurable overhead to all path operations

`showCheckboxColumn` will determine whether or not selectable rows in
DateTable or PaginatedDataTable will contain a leading CheckBox.

https://github.com/flutter/engine/compare/cbdc7bde224c...3851981b863a

git log cbdc7bde224c..3851981b863a --first-parent --oneline
2020-01-04 skia-flutter-autoroll@skia.org Roll fuchsia/sdk/core/mac-amd64 from Vk6uT... to Kom_K... (flutter/engine#15142)


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 franciscojma@google.com on the revert to ensure that a human
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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:
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* add key to constructors of public widgets

* fix a test

* fix a test

cbdc7bde2 Roll src/third_party/skia 7ac038f302f2..6791ee2f8059 (20 commits) (flutter/engine#15141) (#48163)


https://github.com/flutter/engine/compare/eb139936eb2c...cbdc7bde224c

git log eb139936eb2c..cbdc7bde224c --first-parent --oneline
2020-01-04 skia-flutter-autoroll@skia.org Roll src/third_party/skia 7ac038f302f2..6791ee2f8059 (20 commits) (flutter/engine#15141)


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 franciscojma@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

* Added docs on how to set drawer to open only programmatically