Roll Dart SDK from 03e4737f3115 to 59600f2b46ef (54 revisions) (flutter#20143)

Author: skia-flutter-autoroll

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': '03e4737f31151663badde83c5514389f8587efff',
+  'dart_revision': '59600f2b46ef963137be4743c94b99111567043f',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -192,7 +192,7 @@ deps = {
    Var('dart_git') + '/crypto.git@7422fb2f6584fe1839eb30bc4ca56e9f9760b801',
 
   'src/third_party/dart/third_party/pkg/csslib':
-   Var('dart_git') + '/csslib.git@bf372d4fdc6dfa232ad93f77a0a3de0891edd04c',
+   Var('dart_git') + '/csslib.git@451448a9ac03f87a8d0377fc0b411d8c388a6cb4',
 
   'src/third_party/dart/third_party/pkg/dart2js_info':
    Var('dart_git') + '/dart2js_info.git' + '@' + Var('dart_dart2js_info_tag'),

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 0485f6b15a488eabf7ad0b32fbd1b040
+Signature: 35a4acdc8f5708e9c69b73985058bf0b
 
 UNUSED LICENSES: