This is an automated pull request which will automatically merge once checks pass.

Roll src/third_party/dart fedd746..9c14862 (70 commits)

dart-lang/sdk@9c148623c5 prepend missing hex digits error token
dart-lang/sdk@62674b977d Revert "[dartdevc] Immediately throw when encountering an unevaluated constant"
dart-lang/sdk@76128480ae fix bug in invalid constructor initializer recovery
dart-lang/sdk@babefb8c01 [ VM / Service ] Added VMFlagUpdated event to VM stream
dart-lang/sdk@b41b868797 prepend UnmatchedToken error tokens
dart-lang/sdk@04a3f9ee9a 2.4 changelog: be more clear and consistent on breaking changes
dart-lang/sdk@ccdddd2eee Parallel build-mode and DDC changes for summary2.
dart-lang/sdk@ae5d4973ab Improve a diagnostic message by adding specific type information
dart-lang/sdk@3605630e8a [dartdevc] don't clear generic type caches on a hot restart
dart-lang/sdk@7fa49a285a Update the minimum SDK constraint to 2.2.2 for kernel and front_end packages.
dart-lang/sdk@baaeafa2bb Flow analysis: move into front_end.
dart-lang/sdk@24c0507d73 Flow analysis: remove the State.exit method.
dart-lang/sdk@0a2993687b [vm/concurrency] Make all isolates within an isolate group coordinate on GCs
dart-lang/sdk@9ec6a48613 Flow analysis: document the State class
dart-lang/sdk@06b7329fc9 [dart2js, gardening]: Fix dart2js/inferrence/type_mask2_test
dart-lang/sdk@ed38b6d664 Remove KernelMixinApplicationBuilder and KernelNamedTypeBuilder
dart-lang/sdk@0177076f2f [cfe] Merge KernelBodyBuilder into BodyBuilder
dart-lang/sdk@05b5883813 [cfe] Add documentation to some Generator implementations
dart-lang/sdk@c9c0f56f48 [dart/vm] Add 'small string' parameter specifier
dart-lang/sdk@eebbed2d7a Make PropertyDescription constructor parameters named.
dart-lang/sdk@68ba8f9198 [WATCHLISTS] Don't CC dart2js on tests/compiler/dartdevc_native.
dart-lang/sdk@9197c1b021 [dart2js] new-rti: fix TypeEval GVN
dart-lang/sdk@60a952e261 [vm] Avoid superlinear time canonicalizing deep constants.
dart-lang/sdk@730d2c6c6c [vm/bytecode] Fix removal of empty scopes in local variable info
dart-lang/sdk@d3a09dda15 [vm/bytecode] Recognize list factories and set result type for static calls
dart-lang/sdk@0864980e8c Resolve the call method when used with an extension override
dart-lang/sdk@17e15ee9a4 Add outline support for extensions
dart-lang/sdk@41263a4c1a [dart2js] Fix for 37502: double ~/ x returns int
dart-lang/sdk@211190e7ec [vm/bytecode] Reuse ConstantEvaluator instance in bytecode generator
dart-lang/sdk@c2af59f1ea [dart/fuzzer] Add flag to control FP operations
dart-lang/sdk@ee5a90cb1b Flow analysis: test that all variables are registered with add().
dart-lang/sdk@477a3c4748 Revert "[ VM / Service ] Pulled in vm_service_drivers from its own repo."
dart-lang/sdk@722b505316 NNBD migration: Fix an implicit downcast error.
dart-lang/sdk@d7cb52b863 capture more info to debug 37528
dart-lang/sdk@d6c85f4e92 rename dartfix "exclude" option to "excludeFix"
dart-lang/sdk@1e04ff86b0 Mutate Aling(...) and Padding(...) into Container().
dart-lang/sdk@dbeceb1d06 [ VM / Service ] Pulled in vm_service_drivers from its own repo.
dart-lang/sdk@76f82bd0ec [dart2js] Split up runtime_types.
dart-lang/sdk@0352fb2cb7 Fix package dependencies in analyzer_cli, dartfix, nnbd_migration
dart-lang/sdk@3999369c5f [dart/vm] Display test return code on divergence
dart-lang/sdk@d16ad91719 Update DATA_VERSION after summary2 changes to support extensions.
dart-lang/sdk@da58647161 Flow analysis: register loop variables with add().
dart-lang/sdk@1390201177 Support for 'padding' property, and EdgeInsets type.
dart-lang/sdk@91eb2f5fd0 [analyzer] rename the dartfix --include option to dartfix --fix
dart-lang/sdk@53bda39466 Create stream timeout timer before ondata() opeartions
dart-lang/sdk@65d544edea [analyzer] update the analysis server's diagnostic page
dart-lang/sdk@cddd21dde1 [cfe] Merge ExpressionGenerator into Generator
dart-lang/sdk@b52328e528 [cfe] Remove unneeded indirect generator construction through Forest
dart-lang/sdk@2a199f3993 [cfe] Merge KernelExpressionGenerator with ExpressionGenerator
dart-lang/sdk@948b60f8dc [cfe] Add test for extension member parameters
dart-lang/sdk@11755e537c [cfe] Add tests for extension members
dart-lang/sdk@610183d5f9 [cfe] Rename operator[] to getLocalMember on Library/ClassBuilder
dart-lang/sdk@b3b6533c3d [cfe] Create ClassBuilder for extension declarations
dart-lang/sdk@7075ae7026 [cfe+dart2js] Move features to CFE
dart-lang/sdk@b912aebf5c Flow analysis: change tryPromoteToNonNull to promoteToNonNull.
dart-lang/sdk@7adca0ec5f Flow analysis: Remove "emptySet" argument from markNonNullable
dart-lang/sdk@7719298616 Flow analysis: fix incorrectly written unit test.
dart-lang/sdk@073d521131 Update DartType.displayName to display nullability when appropriate
dart-lang/sdk@fe1da36f12 Change the wording of unused-element
dart-lang/sdk@977a78b7a0 Flow analysis: expose State and unit test. Also fix restrict method.
dart-lang/sdk@90f03db962 Support for extensions in summary2.
dart-lang/sdk@f23418d9b7 Flow analysis: Refactor some common unit testing code
dart-lang/sdk@c8587ce199 Flow analysis: don't use == to compare types.
dart-lang/sdk@7b6c667863 Flow analysis: rework tracking of nullability.
dart-lang/sdk@c2e78e83c6 Flow analysis: fix and unit test joinPromoted.
dart-lang/sdk@7976bea0df Add ? suffixes to flow analysis tests.
dart-lang/sdk@507f404361 Flow analysis: always supply a type parameter for FunctionBodyAccess.
dart-lang/sdk@851eaad61a Flow analysis: Rename Element to Variable.
dart-lang/sdk@842812dd0b Flow analysis: Remove unnecessary arg to ifStatement_thenBegin
dart-lang/sdk@0faa3b7153 Flow analysis: Remove hack preventing variables showing as both nullable and non-nullable.