Roll Dart SDK from 9fcac032b669 to cc5df58bd229 (22 revisions)

[skia-flutter-autoroll]

https://dart.googlesource.com/sdk.git/+log/9fcac032b669..cc5df58bd229

2020-06-22 johnniwinther@google.com [cfe] Refactor return type checking in preparation for nnbd spec change
2020-06-22 davidmorgan@google.com Revert "Fix duration.toString() to conform the description"
2020-06-22 sstrickl@google.com [vm/aot] Move precompiled position handling to CodeSourceMap classes.
2020-06-22 karlklose@google.com [infra] Empty SDK commit to validate recipe changes
2020-06-21 brianwilkerson@google.com Add a fix to insert the keyword late
2020-06-21 brianwilkerson@google.com Convert the remaining quick assists to use CorrectionProducer
2020-06-20 kevmoo@google.com Enable v1.9 pedantic lints...
2020-06-20 asiva@google.com Revert "Reland : [VM/Runtime] Cleanup package config initialization code"
2020-06-20 johnniwinther@google.com [cfe] Mark late setters as isGenericCovariantImpl
2020-06-20 zra@google.com Add --track-widget-creation to kernel_front_end.dart
2020-06-20 sra@google.com [benchmark] BigIntParsePrint: Hoist value in all loops
2020-06-20 asiva@google.com Reland : [VM/Runtime] Cleanup package config initialization code
2020-06-20 sra@google.com [dart2js] final locals may be assigned
2020-06-20 asiva@google.com [VM/Runtime] - Fix for issue dart-lang/sdk#42421
2020-06-20 annagrin@google.com Added module information to metadata and use by frontend_sever
2020-06-19 nshahan@google.com [ddc] Normalize T to Never when T extends Never
2020-06-19 zichangguo@google.com [dart:io] HttpClientConnection is destroyed for "CONNECT" request
2020-06-19 fishythefish@google.com [dart2js] Add support for Never as a type literal.
2020-06-19 fishythefish@google.com [dart2js] Visit type parameter bounds in the scope visitor.
2020-06-19 rnystrom@google.com Migrate language_2/type_promotion to NNBD.
2020-06-19 scheglov@google.com Add CiderCompletionComputer.warmUp()
2020-06-19 zichangguo@google.com Fix duration.toString() to conform the description

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC dart-vm-team@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/+doc/master/autoroll/README.md