Roll Dart SDK from ab009483f343 to 746879714c96 (5 revisions) (flutter#27403)

Author: skia-flutter-autoroll

DEPS

@@ -35,7 +35,7 @@ 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': 'ab009483f343d66b5c143756111ad57ca2d4fcb0',
+  'dart_revision': '746879714c967780cf4dfd8f30918a7d462fdde4',
 
   # 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: a4a4f894615dcc3bcefdd50b3dc319f7
+Signature: f431a32022da7478219c9561ef882bac
 
 UNUSED LICENSES:
 
@@ -9932,6 +9932,8 @@ FILE: ../../../third_party/dart/runtime/vm/compiler/compiler_timings.h
 FILE: ../../../third_party/dart/runtime/vm/compiler/ffi/range.h
 FILE: ../../../third_party/dart/runtime/vm/compiler/relocation_test.cc
 FILE: ../../../third_party/dart/runtime/vm/heap/safepoint_test.cc
+FILE: ../../../third_party/dart/runtime/vm/object_graph_copy.cc
+FILE: ../../../third_party/dart/runtime/vm/object_graph_copy.h
 FILE: ../../../third_party/dart/runtime/vm/pending_deopts.cc
 FILE: ../../../third_party/dart/runtime/vm/pending_deopts.h
 FILE: ../../../third_party/dart/runtime/vm/virtual_memory_compressed.cc