Roll src/third_party/dart 44ba80053396..2eba06d26f71 (32 commits)

[skia-flutter-autoroll]

https://dart.googlesource.com/sdk.git/+log/44ba80053396..2eba06d26f71

git log 44ba800..2eba06d --date=short --first-parent --format='%ad %ae %s'
2019-12-16 brianwilkerson@google.com Stop using preview-dir and preview-port values and always open the preview tool
2019-12-16 liama@google.com [analyzer] Use non-nullable experiment when running with nnbd sdk
2019-12-16 regis@google.com [VM/nnbd] Make type Never a regular type.
2019-12-16 mfairhurst@google.com [nnbd_migration] Fix assertion failure in _forTypeParameterSubstitution when not fresh
2019-12-16 sjindel@google.com [vm] Make TFA traces more readable with color-coded scoping.
2019-12-16 mfairhurst@google.com [nnbd_migration] handle downcast from Function to a function type
2019-12-16 mfairhurst@google.com [nnbd_migration] Handle downcast from dynamic to function types
2019-12-16 brianwilkerson@google.com Fix naming of tests around unnecessary new and const fixes
2019-12-16 scheglov@google.com Fix BazelWorkspacePackageTest on Windows.
2019-12-16 brianwilkerson@google.com Add a fix and assist to add a return type
2019-12-16 rmacnak@google.com [vm] Progress toward running without TSAN warnings.
2019-12-16 scheglov@google.com Fix packages tests on Windows.
2019-12-16 whesse@google.com [infra] Fix typo in get_builder_status script
2019-12-16 paulberry@google.com Fix code generators to avoid generating unnecessary consts
2019-12-16 jcollins@google.com Update trial_migration for P1/G1 packages.
2019-12-16 kustermann@google.com [vm/concurrency] Skip isolate tests on hot-reload mode to avoid unnecessary coredumps for CI
2019-12-16 brianwilkerson@google.com Add support to dartfix to fix unnecessary new and const lints
2019-12-16 paulberry@google.com Migration: Modify FixBuilder tests in preparation for rewrite.
2019-12-16 paulberry@google.com Rename TypeProviderImpl._isNonNullableByDefault.
2019-12-16 paulberry@google.com Create an interface for the migration engine to communicate with the resolver.
2019-12-16 paulberry@google.com Make use of ElementTypeProvider in _LocalVariableTypeProvider
2019-12-16 paulberry@google.com Make use of ElementTypeProvider in StaticTypeAnalyzer
2019-12-16 johnniwinther@google.com [cfe+analyzer] Use TryStatement for try/catch and try/finally in CFE
2019-12-16 lrn@google.com Migrate dart:_http to NNBD.
2019-12-16 dimpen@gmail.com Update math.dart:atan2 in relation to atan comment - Follow-up for sdk_nnbd
2019-12-16 dimpen@gmail.com Update math.dart:atan2 in relation to atan comment
2019-12-16 dmitryas@google.com [cfe] Implement the NNBD variation of the assignability property
2019-12-16 johnniwinther@google.com [cfe] Handle setter import conflicts
2019-12-16 johnniwinther@google.com [cfe] Implement flow analysis on if elements
2019-12-16 whesse@google.com [infra] Build status script now queries Firestore, using access token
2019-12-16 athom@google.com [infra] Remove AST builders from the test matrix
2019-12-16 johnniwinther@google.com [cfe] Report errors on nnbd features used in opt-out libraries

Created with:
gclient setdep -r src/third_party/dart@2eba06d26f71

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Bug: None
Tbr: dart-vm-team@google.com

[skia-flutter-autoroll]

Auto-roller completed checks. About to merge.