Roll src/third_party/dart c260e4e8dac6..1db1a837f8c9 (8 commits) (#14606

)

https://dart.googlesource.com/sdk.git/+log/c260e4e8dac6..1db1a837f8c9

git log c260e4e8dac6..1db1a837f8c9 --date=short --first-parent --format='%ad %ae %s'
2019-12-20 kallentu@google.com Added SoundSplayTreeSieve benchmark for variantly sound interfaces.
2019-12-20 scheglov@google.com Issue 39875. Don't report unchecked nullable when resovled to an extension with nullable extended type.
2019-12-20 gityuan@gmail.com support more sync event when use systrace to record timeline event
2019-12-20 brianwilkerson@google.com Simplify the process of adding support for lint-based fixes in dartfix
2019-12-20 paulberry@google.com Introduce EditPlan, a builder class for creating source edits with automatic parenthesis management.
2019-12-20 scheglov@google.com Run all extension tests in NNBD mode too.
2019-12-20 rnystrom@google.com Track files that do not need to be migrated in the NNBD progress script.
2019-12-20 rnystrom@google.com Make selector argument parsing smarter.

Created with:
  gclient setdep -r src/third_party/dart@1db1a837f8c9

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

DEPS

@@ -34,7 +34,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'c260e4e8dac6dfd0ae62a50338f2bc7e055c1e63',
+  'dart_revision': '1db1a837f8c9e7e4e12c968efd98510527feae6b',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 1bc57350d04926bcb0128e3c87bf87f5
+Signature: 4ce155ffc94b91527f6b04e2bb18c102
 
 UNUSED LICENSES:
 
@@ -7460,6 +7460,7 @@ FILE: ../../../third_party/dart/PATENT_GRANT
 FILE: ../../../third_party/dart/benchmarks/IsolateJson/dart/sample.json
 FILE: ../../../third_party/dart/benchmarks/IsolateSpawn/dart/helloworld.dart
 FILE: ../../../third_party/dart/benchmarks/IsolateSpawnMemory/dart/helloworld.dart
+FILE: ../../../third_party/dart/benchmarks/SoundSplayTreeSieve/dart/iterable.dart
 FILE: ../../../third_party/dart/client/idea/.idea/.name
 FILE: ../../../third_party/dart/client/idea/.idea/inspectionProfiles/Project_Default.xml
 FILE: ../../../third_party/dart/client/idea/.idea/vcs.xml
@@ -7546,6 +7547,8 @@ FILE: ../../../third_party/dart/benchmarks/Isolate/dart/Isolate.dart
 FILE: ../../../third_party/dart/benchmarks/IsolateJson/dart/IsolateJson.dart
 FILE: ../../../third_party/dart/benchmarks/IsolateSpawn/dart/IsolateSpawn.dart
 FILE: ../../../third_party/dart/benchmarks/IsolateSpawnMemory/dart/IsolateSpawnMemory.dart
+FILE: ../../../third_party/dart/benchmarks/SoundSplayTreeSieve/dart/SoundSplayTreeSieve.dart
+FILE: ../../../third_party/dart/benchmarks/SoundSplayTreeSieve/dart/sound_splay_tree.dart
 FILE: ../../../third_party/dart/runtime/bin/abi_version.h
 FILE: ../../../third_party/dart/runtime/bin/abi_version_in.cc
 FILE: ../../../third_party/dart/runtime/bin/elf_loader.cc