The number of workers depends on what the platform deem appropriate for the system at runtime.

https://skia.googlesource.com/skia.git/%2Blog/de8362c6f212..10bf7020aa15

git log de8362c6f212b42b03de66a58df29272cb3081be..10bf7020aa154dfbd024df40a33c8f39e5264a47 --date=short --no-merges --format=%ad %ae %s
2019-04-09 jvanverth@google.com Add non-AA support to OvalFactoryOps.
2019-04-09 ethannicholas@google.com ComposeShader GPU implementations
2019-04-09 jvanverth@google.com Add RG format to Metal
2019-04-09 mtklein@google.com extract ToolUtils::colortype_depth()
2019-04-09 bungeman@google.com Build HarfBuzz with multi-thread support.

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

1490a90bc1 Track guards using NullabilityNode rather than ConstraintVariable.
7f224d9fbe Track parameters that might need to be made optional/required using NullabilityNode.
6c063512ae Validate that nullability is propagated from optional/required named parameters.
ed7f524afb Refactor more of the migration tool to use NullabilityNode rather than ConstraintVariable.
78c55022b1 [VM] - Fix for issue 36484 exposed when ExperimentalFlag.constantUpdate2018 is turned on in CFE
a7175938c3 Remove use of package_root in analyzer/test/error_test
45a5349175 Track constant field initializers for field analysis.
91c042c066 Implement isCovariant for fields.

This used to be when we had two text shaping engines.

https://skia.googlesource.com/skia.git/%2Blog/b5d8c634f95b..de8362c6f212

git log b5d8c634f95b008882710cb27b6094b3f69d1a85..de8362c6f212b42b03de66a58df29272cb3081be --date=short --no-merges --format=%ad %ae %s
2019-04-09 mtklein@google.com remove DMJsonWriter::AddTestFailure
2019-04-09 bsalomon@google.com Temporarily make TransferPixelsFromTest read BGRA as RGBA on ES.
2019-04-09 reed@google.com remove def of colorfilter flag
2019-04-09 reed@google.com New factories for SkShaders
2019-04-09 nifong@google.com full collection of externs
2019-04-08 herb@google.com Reland "Handle translating blob to origin in bulk"
2019-04-09 halcanary@google.com SkPDF: move annotations away from device.
2019-04-09 mtklein@google.com some refactoring ideas
2019-04-09 ethannicholas@google.com SkSL 'key' variables can now be controlled by 'when' expressions
2019-04-09 fmalita@chromium.org Revert "[skottie] More snug kTop Shaper alignment"
2019-04-09 halcanary@google.com SkPDF: remove unused field
2019-04-09 egdaniel@google.com Fix to barrier batching.
2019-04-09 mtklein@google.com --parameters -> --properties
2019-04-09 michaelludwig@google.com Detect simpler quad type when possible

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

Some components in the Flutter engine were derived from the forked blink codebase. While the forked components have either been removed or rewritten, the use of the blink namespace has mostly (and inconsistently) remained. This renames the blink namesapce to flutter for consistency. There are no functional changes in this patch.

Creating fonts can take a long time (50ms+) during frame build in the UI
thread.  Trace them to help us understand when it's causing a jank.

https://skia.googlesource.com/skia.git/%2Blog/9a7c7be15969..b5d8c634f95b

git log 9a7c7be15969e1e0bad0b7a5c6bb40e254265838..b5d8c634f95b008882710cb27b6094b3f69d1a85 --date=short --no-merges --format=%ad %ae %s
2019-04-08 reed@google.com remove guard for bitmap shader api
2019-04-09 bsalomon@google.com Add support for importing GL_R16F for YUVA promise images
2019-04-04 martin@mainframe.co.uk add missing shared lib visibility macros
2019-04-09 herb@google.com Revert "Handle translating blob to origin in bulk"
2019-04-09 herb@google.com Revert "Reland "Do not use sub-pixel positioning for source space""
2019-04-09 skia-autoroll@skia-public.iam.gserviceaccount.com Roll skia/third_party/skcms 36eeb1311a72..0da672fc2c69 (1 commits)
2019-04-09 herb@google.com Reland "Add maxDimension() to glyph"
2019-04-09 herb@google.com Reland "Do not use sub-pixel positioning for source space"
2019-04-08 brianosman@google.com Shader serialization experiment (with Mali Offline Compiler analysis)
2019-04-09 reed@google.com Revert "Do not use sub-pixel positioning for source space"
2019-04-09 reed@google.com Revert "Add maxDimension() to glyph"

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

* switch to newer APIs for shaders and filters

* fix formatting

https://skia.googlesource.com/skia.git/%2Blog/097e77cd3ba0..9a7c7be15969

git log 097e77cd3ba09f7b81025ecd52d73fa5511e9161..9a7c7be15969e1e0bad0b7a5c6bb40e254265838 --date=short --no-merges --format=%ad %ae %s
2019-04-09 robertphillips@google.com Revert "Skip flush in GrDrawingManager if the specifed proxy doesn't have any work"

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

https://skia.googlesource.com/skia.git/%2Blog/696e8dda3ca3..097e77cd3ba0

git log 696e8dda3ca30438f440777bd17e69e5ccd748c1..097e77cd3ba09f7b81025ecd52d73fa5511e9161 --date=short --no-merges --format=%ad %ae %s
2019-04-09 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

https://skia.googlesource.com/skia.git/%2Blog/0ea414a08208..696e8dda3ca3

git log 0ea414a082083f56ea2ab18828192d020b50e69f..696e8dda3ca30438f440777bd17e69e5ccd748c1 --date=short --no-merges --format=%ad %ae %s
2019-04-09 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 4ba1911b2d7f..eba396cc66d3 (3 commits)
2019-04-09 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 90b1865e2a8b..82418c821689 (8 commits)
2019-04-09 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ../src afd96fdcf75a..79154509c679 (442 commits)

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

When running on Fuchsia, "fml/trace_event.h" sends trace events towards
Fuchsia's tracing system, rather than its own |fml::tracing::*| one.  Do
the same thing for |FlutterEventTracer|, in order to unlock category
"skia" trace events when running on Fuchsia.

The reason this was not working before is because |FlutterEventTracer|
was directly using |fml::tracing::*| functions, rather than the
TRACE_EVENT_* macros.

In the future, we can look into having the skia event tracer enabled by
default on Fuchsia, controlling the presence of Skia events by
enabling/disabling the "skia" category, once we measure the performance
cost of doing so.

https://skia.googlesource.com/skia.git/%2Blog/2f08a4043b26..0ea414a08208

git log 2f08a4043b26370aa24f713f5960433af8dd398f..0ea414a082083f56ea2ab18828192d020b50e69f --date=short --no-merges --format=%ad %ae %s
2019-04-08 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-04-08 fmalita@chromium.org [skottie] More snug kTop Shaper alignment

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

cc63d6e647 dart fix support for control_flow_collection fixes
6d941f8099 Add manifest file error codes to master list of errors
e9765499cc Support for name offset, code offset/length, documentation.
cb894430ae error code associations for ui as code lints
29a6ad3beb Lazy AstBinaryReader is always lazy.
8f3608ca25 Enable ddb to run with experiments
de6a7feb24 [vm] Add assertion to check if number of type arguments was calculated before setting type parameters
86734d476b [infra] Remove obsolete tools/infra/config directory

Looks like someone added a new use of the method while I was waiting for flutter
to roll. nuking the last instance so i can move forward with deprecating and
removing it.

b23817105c Build types for function typed formal parameters.
93b4c5ca57 [vm] Improve error message for Dart_PropagateError with no exit frame.
3dd09e2a3d Follow up on change https://dart-review.googlesource.com/c/sdk/+/98623 to fix a failing Windows test
94c34d3cbe Introduce a getter on the Variables class to represent types that are a priori known to be non-nullable.
3ffe59e1e9 Fix for URIs of parts.
f1f297e213 Build export elements and combinators.
762acf00e8 Restore computing export scopes.
959cf5967d Simplify strong_test_helper

https://skia.googlesource.com/skia.git/%2Blog/6b797fec83f0..2f08a4043b26

git log 6b797fec83f05cd1c57e0d5505a0f69b9f753c78..2f08a4043b26370aa24f713f5960433af8dd398f --date=short --no-merges --format=%ad %ae %s
2019-04-08 gkaiser@google.com examples: Avoid undefined behavior
2019-04-08 reed@google.com undef guard for bitmap shader
2019-04-08 reed@google.com Introduce new factory for SkColorFilters
2019-04-08 herb@google.com Add maxDimension() to glyph
2019-04-08 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-04-08 csmartdalton@google.com Disable output swizzling from GrDisableColorXP
2019-04-08 brianosman@google.com Update SPIRV caching to use SkWriter32/SkReader32 and allow inspection
2019-04-08 skia-autoroll@skia-public.iam.gserviceaccount.com Roll skia/third_party/skcms 99740cdf2835..36eeb1311a72 (1 commits)

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

Android Embedding PR26: Offer an async version of FlutterMain's ensure initialization complete. (#8465)

aacc0b0709 Index more declarations and build more scopes.
b2df6eddda Make a new "nullability node" abstraction for the migration tool.
258d2f121b Rewrite more element model to using AST.
27a58d455d [vm/aot] Remove special casing of td views, allow external/internal typed data to be fast as well in string decoding

https://skia.googlesource.com/skia.git/%2Blog/602df41025ea..6b797fec83f0

git log 602df41025eadb33e872d0314c340d526c740183..6b797fec83f05cd1c57e0d5505a0f69b9f753c78 --date=short --no-merges --format=%ad %ae %s
2019-04-08 brianosman@google.com Simplify persistent cache code, make GLSL easier for tools to access
2019-04-08 csmartdalton@google.com Add a mustWriteToFragColor() workaround flag
2019-04-08 bsalomon@google.com Start on supporting transfer from GrSurface.
2019-04-08 reed@google.com add flag to stage API change
2019-04-08 herb@google.com Do not use sub-pixel positioning for source space
2019-04-08 reed@google.com extend guard to makeAsALocalMatrixShader for google3
2019-04-08 halcanary@google.com SkPDF: device to use SkTCopyOnFirstWrite<SkPaint>
2019-04-08 nifong@google.com add SkpFilePlayer to externs
2019-04-08 reed@google.com add makeShader() to SkBitmap, and deprecate SkShader version
2019-04-08 herb@google.com Handle translating blob to origin in bulk
2019-04-08 robertphillips@google.com Skip flush in GrDrawingManager if the specifed proxy doesn't have any work
2019-04-08 kjlubick@google.com Initialize unfilled textures based on GrCaps
2019-04-08 michaelludwig@google.com Reland "Support clip masks for SaveLayerRec and drawSpecial in Ganesh"
2019-04-08 ethannicholas@google.com Revert "Reland "Revert "Reland "GPU support for SkMixers""""
2019-04-08 reed@google.com Revert "Revert "Move localmatrix routines to shaderbase, no need to be public.""
2019-04-08 ethannicholas@google.com fixed ArithmeticImageFilter input type
2019-04-07 nigeltao@google.com Update Wuffs version
2019-04-08 mtklein@google.com fm_bot: look for and explain too-late flags
2019-04-08 reed@google.com Reland "Revert "Move localmatrix routines to shaderbase, no need to be public.""

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

As there are extra requirement to use playInputClick in iOS, use AudioServicesPlaySystemSound instead to play input sound.

Adds `Locale.toLanguageTag()`, which returns a valid Unicode Locale Identifier
using underscores as separator that can be reliably parsed.

8e4dcf48c4 [vm/compiler/aot] Fix unboxing of int32/uint32 in typed data specializer
287c9de1b2 [infra] Update checked in SDKs to 2.2.1-dev.3.1
6d47db7629 bump to linter 0.1.85
4ca7401604 [co19] Roll to 7e743ef29b4c06f1a2b8b9dc70ead60b31aab526
94baf382cc Revert "Revert "set empty environment defines to CompilerOptions""
fadae89a38 Remove unused imports
26874860e3 [SDK] Adds .exe extension for Windows binaries in dart_sdk.py.
d75a49a44f [CFE] Ignore abstract methods when looking for operator '=='.

https://skia.googlesource.com/skia.git/%2Blog/053b2939938c..602df41025ea

git log 053b2939938ca55cbc7aa1457628c4c3a1bcd7fa..602df41025eadb33e872d0314c340d526c740183 --date=short --no-merges --format=%ad %ae %s
2019-04-08 robertphillips@google.com Reduce the number of flush entry points
2019-04-08 kjlubick@google.com [pathkit] build with newer emscripten
2019-04-05 reed@google.com Revert "Revert "Move localmatrix routines to shaderbase, no need to be public.""
2019-04-08 mtklein@google.com fix -script parsing
2019-04-06 masonfreed@chromium.org Added the ability to set the entire matrix at once
2019-03-26 jvanverth@google.com Enable fixed tests on Metal
2019-04-08 robertphillips@google.com Reland "Revert "Reland "GPU support for SkMixers"""
2019-04-08 ethannicholas@google.com Revert "Revert "Reland "GPU support for SkMixers"""
2019-04-08 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset
2019-04-08 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/angle2 fb201c5e208d..90b1865e2a8b (10 commits)
2019-04-08 skia-autoroll@skia-public.iam.gserviceaccount.com Roll ../src 3e2882be2dde..afd96fdcf75a (504 commits)
2019-04-08 skia-autoroll@skia-public.iam.gserviceaccount.com Roll third_party/externals/swiftshader 0e3d328ac338..4ba1911b2d7f (14 commits)
2019-04-07 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update SKP version
2019-04-07 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset
2019-04-06 skia-recreate-skps@skia-swarming-bots.iam.gserviceaccount.com Update go_deps asset
2019-04-05 recipe-mega-autoroller@chops-service-accounts.iam.gserviceaccount.com Roll recipe dependencies (trivial).
2019-04-05 masonfreed@chromium.org Made the fTypeMask field non-lazily computed.
2019-04-05 michaelludwig@google.com Revert "Support clip masks for SaveLayerRec and drawSpecial in Ganesh"
2018-05-07 halcanary@google.com SkString: simplify impl
2019-04-05 khushalsagar@chromium.org remote fonts: Validate format on deserialized glyph.
2019-04-05 jvanverth@google.com Fix WritePixels and ReadPixels for MacOS Metal

The AutoRoll server is located here: https://autoroll.skia.org/r/skia-flutter-autoroll

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

If the roll is causing failures, please contact the current sheriff (egdaniel@google.com), and stop
the roller if necessary.

8e0a669e74 Revert "[vm] Refactor Location to use either dart::Register or dart::host::Register"
3e12bdd717 Update `dart2aot` help output
50f3a6c960 [gardening] Make deferred imports part of the corresponding tests.
60b3643e8e [vm] Refactor Location to use either dart::Register or dart::host::Register
544371c7f2 [vm] Refactor constants to be available in namespaces dart and dart::host
7f5ed18ffc [release] Update changelog to match dev branch

86b5304ccd Revert "Fix mustCallSuper for mixins and inherited interfaces:"
389ccc9000 when analyzing fuchsia workspaces, expect to find .fx-build-dir files
a47b4ad2b8 Bring dart_style 1.2.7 into the SDK repo.
e5d78513a1 [dartdevc] Hoisting covariance checks for generators outside of the body.
73b931b6e6 Start reworking to use actual AST nodes created lazily.
fd2393d6d3 [dart/fuzzer] Re-enable optimization_counter_threshold testing
8e6851f0e4 [vm] Don't create edge counter arrays when edge counters are disabled.
90c757c766 [vm, interpreter] Allocation fast paths.
43046b7f7c [vm/bytecode] Enable building of kernel service snapshot
7beed016a0 [vm/bytecode] Add 'bytecode' into snapshot feature flags
cf04a16527 dartfix to migrate to spread collections
9e1adc54a7 [vm] When loading a compilation trace, speculatively populate ICData based on the receiver's static type.
f93b93dd91 [dartdevc] fix string escaping for string_literal_test
4b9b8562c6 Update expectation for conditional expression and constant_update_2018.
da4ccd0855 [analyzer] fix #32918, eliminate type variables during const inference
0e7bec7d2f Add validation for AndroidManifest.xml files
ca4e707e80 Fix AvailableSuggestionSetsTest on Windows.
d4c61411f3 Update bug number to reflect deprioritized bug
ee248fef23 Add a fix for using relative imports when the missing import is in the same library.
07482eeb5e [bots] Run all tests on vm-dartkb-* bots
1ad11facec Fix mustCallSuper for mixins and inherited interfaces:
6dc9c8d127 [CFE] JS: Treat integer valued double constants as integers.
dbfd00f44d [vm/compiler] Add new optimization pass which inlines typed data accesses
dbc9ff11bf [vm/vmservice] Switch from const bool.fromEnvironment() to new for 'DART_SERVICE_USE_AUTH'.
44799241fa Revert "set empty environment defines to CompilerOptions"
ec8222f457 bump to linter 0.1.84
d14990b3ad Remove no-longer-needed override

The dart revision 1ad11facec401ed51a8bdf79dafd77e955b23082
(rolled in https://github.com/flutter/engine/pull/8459) is causing
engine-to-framework roll failure for the following two reasons:

1. analyze error: marked @mustCallSuper but does not invoke the overridden method
2. `flutter build aot` failure for examples/hello_world in build_tests-macos

The 1. is likely due to
https://github.com/dart-lang/sdk/commit/1ad11facec401ed51a8bdf79dafd77e955b23082
and it easy to fix in the framework.

However, the 2. is likely due to
https://github.com/dart-lang/sdk/commit/dbfd00f44daf67e5f42f4d297d77be3237b8a35d
which I'm not sure how to fix.

TBR: bkonyi

389ccc9000 when analyzing fuchsia workspaces, expect to find .fx-build-dir files
a47b4ad2b8 Bring dart_style 1.2.7 into the SDK repo.
e5d78513a1 [dartdevc] Hoisting covariance checks for generators outside of the body.
73b931b6e6 Start reworking to use actual AST nodes created lazily.
fd2393d6d3 [dart/fuzzer] Re-enable optimization_counter_threshold testing
8e6851f0e4 [vm] Don't create edge counter arrays when edge counters are disabled.
90c757c766 [vm, interpreter] Allocation fast paths.
43046b7f7c [vm/bytecode] Enable building of kernel service snapshot
7beed016a0 [vm/bytecode] Add 'bytecode' into snapshot feature flags
cf04a16527 dartfix to migrate to spread collections

9e1adc54a7 [vm] When loading a compilation trace, speculatively populate ICData based on the receiver's static type.
f93b93dd91 [dartdevc] fix string escaping for string_literal_test
4b9b8562c6 Update expectation for conditional expression and constant_update_2018.