Roll dart to 3e6b8717fedce5cc28a21616f4591683c211f752 (#4940)

3e6b8717fe Fixed GamePadList not working in DDC and hide MessagePort.start operation.
edb6e776f1 Update parseFields to use typeInfo
fdc787efc8 Adjusted issue numbers of a test
22d99d8920 Update status for LUCI versions of dart2js chrome builders
20ea3f5d69 Pass a list of context messages in onProblem callback.
bbb281ff3b Error reporting functions take a list of context messages.
83ef97f873 Wrap a formatted message with line and column in a FormattedMessage.
b2d7749643 Fix issue with missing sources
765242d1b0 Add an issue template to the SDK
3acccedc40 Mark IsolateReload_TearOff_Parameter_Count_Mismatch failing
006fda374b Update test matrix with correct path to dart on Mac OS
4d7327b7b7 Run inference test in strong mode
c502578096 Replace skipTypeReferenceOpt with computeType
7ed7e57aaa Assert that inference isn't expected on abstract methods.

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': '2676c132cbfd88befcecc544b2e902c255e44b34',
+  'dart_revision': '3e6b8717fedce5cc28a21616f4591683c211f752',
 
   'dart_args_tag': '1.4.1',
   'dart_async_tag': '2.0.6',

travis/licenses_golden/licenses_third_party

-Signature: 3fc14486250c20c91df483399a9ffd9b
+Signature: e57916cfc106e31b9115fb6ab9ec28cb
 
 UNUSED LICENSES: