Roll src/third_party/dart b3396cbdcae1..49850e6919f7 (45 commits)

[skia-flutter-autoroll]

https://dart.googlesource.com/sdk.git/+log/b3396cbdcae1..49850e6919f7

git log b3396cb..49850e6 --date=short --first-parent --format='%ad %ae %s'
2020-02-06 bkonyi@google.com [ VM / Service ] Fixed mismatching type in migrated NNBD service code
2020-02-06 joshualitt@google.com Fix minor bug with NNBD and Math.exp
2020-02-06 zichangguo@google.com Revert "fix hanging of write on Windows"
2020-02-06 mfairhurst@google.com [analyzer] Fix #32913, no error for inferring a non-const type argument in a generic function used in a const location
2020-02-06 mfairhurst@google.com [analyzer] Add a recursive type visitor that can be stopped midtraverse.
2020-02-06 devoncarew@google.com [front_end] fix a long line in a test helper file
2020-02-06 zichangguo@google.com fix hanging of write on Windows
2020-02-06 scheglov@google.com Extract SwitchStatement errors into separate files.
2020-02-06 jsimmons@google.com [vm] Bring back the Fuchsia implementation of File::OpenStdio
2020-02-06 brianwilkerson@google.com Add an assist to shadow a field when a local variable might be promotable
2020-02-06 alexmarkov@google.com [vm/aot/tfa] Tree shake write-only fields
2020-02-06 rnystrom@google.com Create a package_config.json file for the SDK tests.
2020-02-06 jwren@google.com [completion metrics] Add a simple CLI at the start of completion_metrics.dart. This will allow run configurations in IntelliJ hold onto the directory paths instead of being hard coded.
2020-02-06 scheglov@google.com Analyze SDK with non-nullable experiment enabled, update MockSdk.
2020-02-06 liama@google.com [vm] Reland NNBD flag flip
2020-02-06 sjindel@google.com [vm] Don't use write barrier for stores of nullable bools.
2020-02-06 sortie@google.com [dart:io] [vm] Fix poll(2) loop while waiting for a process to exit.
2020-02-06 rnystrom@google.com Migrate lib_2/typed_data/typed_data_view_sublist_test.dart to NNBD.
2020-02-06 jensj@google.com [CFE] Update expectations caused by two CLs landing at the same time
2020-02-06 johnniwinther@google.com [cfe] Add test for Never in opt-out code
2020-02-06 athom@google.com [co19] Roll co19 to def1183bacc28f008db4fdd3d0442ed05f1889f8
2020-02-06 johnniwinther@google.com [kernel] Add Class.hasConstConstructor and Member.isNonNullableByDefault predicates
2020-02-06 jensj@google.com [CFE] Allow experimental invalidation to work on DillLibraryBuilders
2020-02-06 dacoharkes@google.com [vm] Arm Assembler simplify code for SubImmediateSetFlags
2020-02-06 sstrickl@google.com [vm/compiler] Fix parsing of Unicode escapes in S-expressions.
2020-02-06 dmitryas@google.com [cfe] Move isTop, isBottom, isObject, and isNull to CoreTypes
2020-02-06 jensj@google.com [cfe] Quick standalone deps calulation
2020-02-06 dmitryas@google.com [cfe] Warn about non-nullable operands in null-aware operations
2020-02-06 karlklose@google.com Minor edit in README.md
2020-02-06 victor.agnez@hotmail.com Refactor Instruction::speculative_mode()
2020-02-06 johnniwinther@google.com [cfe] Don't check override for member signatures.
2020-02-06 bkonyi@google.com [ DartFuzz ] Disable floating point operations when comparing different architectures
2020-02-06 regis@google.com [VM/nnbd] Consider nullability of type parameters in function type tests.
2020-02-06 scheglov@google.com Fix for constant dependencies when opt-out depends on opt-in.
2020-02-06 pquitslund@google.com completion driver wip
2020-02-06 jwren@google.com Initial working 'dartdev format *' tool with the set of args and flags to match the 'flutter format *' tool
2020-02-06 bkonyi@google.com Reland "[ VM / DartDev ] Added support for format and pub commands via standalone VM"
2020-02-05 rmacnak@google.com [vm] Don't hold IdleTimeHandler::mutex_ when entering a safepoint.
2020-02-05 kustermann@google.com [vm/concurrency] Fix bug in Safepoint{Mutex,Monitor}Locker which can cause a deadlock
2020-02-05 asiva@google.com [VM/libraries] - Fix signature of waitFor.
2020-02-05 jcollins@google.com Use analyzer filesystem implementation.
2020-02-05 fishythefish@google.com [dart2js] Remove type unaliasing.
2020-02-05 kustermann@google.com [vm/concurrency] Make some service tests more robust
2020-02-05 devoncarew@google.com [nnbd migration] add an initial readme to describe the workflow and tool
2020-02-05 paulberry@google.com Migration: propagate non-null intent into function literals.

Created with:
gclient setdep -r src/third_party/dart@49850e6919f7

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/+/master/autoroll/README.md

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