Roll Dart to revision 2.7.2, remove duplicate dependencies

.cirrus.yml

@@ -52,6 +52,9 @@ task:
         mkdir -p $FRAMEWORK_PATH
         cd $FRAMEWORK_PATH
         git clone https://github.com/flutter/flutter.git
+        # following lines only for hotfix branch!
+        cd $FRAMEWORK_PATH/flutter
+        git checkout v1.12.13-hotfixes
       test_web_script: |
         cd $FRAMEWORK_PATH/flutter/dev/integration_tests/web
         ../../../bin/flutter config --local-engine=host_debug_unopt --no-analytics --enable-web

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': '4cc36055d6803b899667feaedc1216a96e9d1c72',
+  'dart_revision': '1c9356d8990a2a8c90c66097e20cb2f22e5cc267',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
@@ -494,26 +494,6 @@ deps = {
      'dep_type': 'cipd',
    },
 
-   'src/third_party/dart/tools/sdks': {
-     'packages': [
-       {
-         'package': 'dart/dart-sdk/${{platform}}',
-         'version': 'version:2.4.0'
-       }
-     ],
-     'dep_type': 'cipd',
-   },
-
-   'src/third_party/dart/pkg/analysis_server/language_model': {
-     'packages': [
-       {
-        'package': 'dart/language_model',
-        'version': 'lIRt14qoA1Cocb8j3yw_Fx5cfYou2ddam6ArBm4AI6QC',
-       }
-     ],
-     'dep_type': 'cipd',
-   },
-
   'src/flutter/third_party/gn': {
     'packages': [
       {

ci/licenses_golden/licenses_third_party

@@ -1,4 +1,4 @@
-Signature: 4e55b5baef1fa7d7d9610d567650b3b6
+Signature: 7903c4f4860eff2e05d6de9d49a2b26c
 
 UNUSED LICENSES: