Dart SDK roll for 2019-01-07

3cec3dd5bf Issue 35548. Don't report CONST_CONSTRUCTOR_WITH_MIXIN_WITH_FIELD when mixin has a static field.
f715a2e79e Include experiments into AnalysisOptions.unlinkedSignature.

DEPS

@@ -31,7 +31,7 @@ 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': 'e541849a9f37c28a90163c663acf3ba1f16b5430',
+  'dart_revision': '3cec3dd5bffe42405e47437f054412e2e7eb1520',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py