Roll dart sdk to 4c9689c (flutter#5559)

* Roll dart sdk to 4c9689c

Changes since last roll:
```
4c9689c [vm] Support pluggable expression compiler for `evaluate` service api call.
d70c38e [Gardening] Mark test as flaky on also non-kernel (legacy)
060ee67 Make CastStreamSubscription.onData handle a null callback
f7289aa Remove specification of naming conventions.
8713178 Add appendix to spec which specifies JavaScript integer behavior.
dfeaf79 Fix VM accepting too many overlarge hex numbers in int.parse.
c84a9f4 Recompute ClassHierarchy after adding noSuchMethod forwarding stubs
b558a9c Handle missing compile-time errors
3df126c [gardening] Update status for vm-kernel-linux-debug
e227067 Treat objects with .call as "subtypes" of function types
b960e5a [gardening] Mark standalone_2/io/directory_test as Crash on dartkp/debug
e2d72aa Prepare tools/bots/try_benchmarks.sh for Dart 2.
de5f9ea Add --use-fasta-parser flags to dartanalyzer and the analysis server.
e2d903c Remove packages/ directory resolution from CFE
aabb78f Update checked-in SDK to 2.0.0-dev.63.0 on mac and linux.
bc8d772 Improve flags documentation, reenable hints in dart2js.
209a602 Tweak for fixes tests - use orElse to avoid exception.
0e4c158 Issue 33458. Suggest 'Create Class' Quick Fix for creation without new.
44650cc Pass the location of vm_platform to compile_platform from the commandline.
0bac650 switch to dart_action until prebuilt Windows Dart VM is updated
82ed18c Update checked-in Windows SDK to 2.0.0-dev.63.0
2394097 Support for including/excluding the same path in ContextRoot.isAnalyzed().
f59389b Optimize .runtimeType impact based on usage
ee1f7f5 Fix newly reported warnings
afa8ff6 Add a resource provider that supports file overlays
a63cf8e Add --no-preview-dart-2 flag.
2a396d5 [vm/intrinsics] Intrinsify 64-bit int typed data.
dd8988c - Moved all WebGL rendering/drawing constants to synthesized class WebGL. - Removed obsolete Dartium/_blink code.
541dd19 Enable creating full kernel files in addition to outlines from the bazel worker for kernel.
8e9e8e1 Fix various bugs and regularize behavior of returns statements in various kinds of functions.
f1d1da6 [vm/precomp] Reduce the size of slow-path code in precompiled mode.
b51d3d4 Key string should be avoided
1e906c3 Add no-op entry point for IncrementalCompiler
aeeb7ba Change error message to not use imperative tone
309baed Mark some frequently flaky co19 dart2js tests.
1a08341 Analyzer status file update
ac039ab Add option to check if a dill is self-contained
f479435 - Removed custom handling of fill - it was wrong the method is now overloaded. - Associate the JS class SpeechSyntesisVoice with the correct Dart class (DDC). - Top-level querySelectorAll wasn't generic. - Handle "static" for attributes in the IDLs.
d2a3723 optimize await in async* methods in dartdevc
8f0106e Update more Analyzer fasta tests
53c2a6f Cleanup remaining unescape string call sites
1ef4399 Run dartfmt --fix for dart2 on pkg/dev_compiler
38eda19 Fix resolve_input_uri_test on windows.
5bf6436 Initial implementations of two generators
03bcc49 [fuchsia] Migrate process creation to fdio_spawn_vmo
0cf860f Remove pub_build_validity test
c015e8d Improve invalid string literal error recovery
84f0778 Update CHANGELOG.md for 2.0.0-dev.63 release
7757fa7 [vm] Remove redundant Profiler::DumpStackTrace().
2bc9025 Consider initializing formals during top-level type inference
9df6426 Mark the library analyzer.dart as being deprecated
bd95662 Remove code that is causing a couple of hints
d99aeb3 [kernel] Update Fuchsia suspend to use new API.
6f44d3f Issue 2287. Move all, but constructors and fields set in constructors, from StatelessWidget into State.
729e994 Support multiple files in messages test.
99575f7 Split ContextAwareGenerator and its subclasses
41a8b79 Use the inferred type of const lists/maps to for constant evaluation.
2972ca6 Fix continue in invalidation logic
c54a302 [VM] Evaluate symbols in kernel2kernel constant evaluator in AOT (even in non-const contexts)
4a7ccd5 Deleted TODO comment in Scoping
8dca855 Specify dynamic type of Futures/... returned from async/... functions
385d825 Make frontend_server initialize from dill work again
2716b6f Add test to frontend_server that mimics the flutter benchmarks
17d2839 Fixed tests for FF difference.
6779ea0 GN rules: add libraries_specification_uri argument to the  compile_platform template.
12b33ad [VM interpreter] Support NativeCall kernel bytecode.
db72134 [vm/inliner] Add smi return type of clamped convertors.
33feee3 [vm/kernel/bytecode] Fix arguments passing in native factory constructors
c30ce41 Add hook to use single-root in fasta scripts and make use of it when creating the dart2js platform files.
34ee27a Update to the latest pub
bfb9a4e linter 0.1.53
dfe6385 Fix a Dart 2 runtime cast failure
f7ef66f Issue 33412. Fix for race condition in knownFiles during search.
aca417a Fix test and expected failure.
664f756 [vm] Reduce maximum new generation size and growth rate.
bd603ba Record dependencies via CompilerContext
```

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': '4b2d60cb18e418c5cb92cf22d2d959d8b70142a3',
+  'dart_revision': '4c9689c1d2da97d0aa25cf16cc90c2e463ad157f',
 
   'dart_args_tag': '1.4.1',
   'dart_async_tag': '2.0.7',
@@ -73,7 +73,7 @@ vars = {
   'dart_plugin_tag': '0.2.0+2',
   'dart_pool_tag': '1.3.4',
   'dart_protobuf_tag': '0.7.1',
-  'dart_pub_rev': '881a0c3fbe63af07dd043b3f5e6cbe74eacb377c',
+  'dart_pub_rev': '8b9526c915bf21627a20cd0104cb6c2be25a879f',
   'dart_pub_semver_tag': '1.4.1',
   'dart_quiver_tag': '5aaa3f58c48608af5b027444d561270b53f15dbf',
   'dart_resource_rev': 'af5a5bf65511943398146cf146e466e5f0b95cb9',

lib/snapshot/BUILD.gn

@@ -219,9 +219,7 @@ source_set("snapshot") {
 }
 
 compile_platform("non_strong_platform") {
-  sources = [
-    "libraries.json",
-  ]
+  libraries_specification_uri = "libraries.json"
 
   outputs = [
     "$root_out_dir/flutter_patched_sdk/platform.dill",
@@ -235,9 +233,7 @@ compile_platform("non_strong_platform") {
 }
 
 compile_platform("strong_platform") {
-  sources = [
-    "libraries.json",
-  ]
+  libraries_specification_uri = "libraries.json"
 
   outputs = [
     "$root_out_dir/flutter_patched_sdk/platform_strong.dill",

travis/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 06e26696632aa476c173d6379a190aac
+Signature: 624f651136a86d0ec2cbb3d8d21f3c50
 
 UNUSED LICENSES: