Version 2.12.0-183.0.dev

Merge commit '30c4006d52fad4ee8b92025933b9f17af7a8740f' into 'dev'
diff --git a/DEPS b/DEPS
index 2e725ab..027149c 100644
--- a/DEPS
+++ b/DEPS
@@ -164,7 +164,7 @@
   "watcher_rev": "1fb0a84acd8d195103f10aba03ba6bd6fdb424e5",
   "webdriver_rev": "5a8d6805d9cf8a3cbb4fcd64849b538b7491e50e",
   "web_components_rev": "8f57dac273412a7172c8ade6f361b407e2e4ed02",
-  "web_socket_channel_rev": "490061ef0e22d3c8460ad2802f9948219365ad6b",
+  "web_socket_channel_rev": "680358915e331fda823908234f80beba1ed4ec83",
   "WebCore_rev": "fb11e887f77919450e497344da570d780e078bc8",
   "yaml_rev": "cca02c9e4f6826d62644901ed65c6d72b90a0713",
   "zlib_rev": "c44fb7248079cc3d5563b14b3f758aee60d6b415",
diff --git a/pkg/analyzer_cli/lib/src/driver.dart b/pkg/analyzer_cli/lib/src/driver.dart
index 1115b86..cd9a1cc 100644
--- a/pkg/analyzer_cli/lib/src/driver.dart
+++ b/pkg/analyzer_cli/lib/src/driver.dart
@@ -22,7 +22,6 @@
 import 'package:analyzer/src/dart/analysis/performance_logger.dart';
 import 'package:analyzer/src/dart/analysis/results.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart';
-import 'package:analyzer/src/file_system/file_system.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/interner.dart';
 import 'package:analyzer/src/generated/java_engine.dart';
diff --git a/pkg/analyzer_cli/tool/perf.dart b/pkg/analyzer_cli/tool/perf.dart
index bd94085..e4e3dcb 100644
--- a/pkg/analyzer_cli/tool/perf.dart
+++ b/pkg/analyzer_cli/tool/perf.dart
@@ -17,7 +17,6 @@
 import 'package:analyzer/src/dart/scanner/reader.dart';
 import 'package:analyzer/src/dart/scanner/scanner.dart';
 import 'package:analyzer/src/dart/sdk/sdk.dart' show FolderBasedDartSdk;
-import 'package:analyzer/src/file_system/file_system.dart';
 import 'package:analyzer/src/generated/parser.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
diff --git a/pkg/telemetry/test/telemetry_test.dart b/pkg/telemetry/test/telemetry_test.dart
index 7a9b70a..8cd4ca3 100644
--- a/pkg/telemetry/test/telemetry_test.dart
+++ b/pkg/telemetry/test/telemetry_test.dart
@@ -6,7 +6,6 @@
 
 import 'package:telemetry/telemetry.dart';
 import 'package:test/test.dart';
-import 'package:usage/usage.dart';
 
 void main() {
   group('telemetry', () {
diff --git a/tools/VERSION b/tools/VERSION
index 3c69ed8..efc228c 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 12
 PATCH 0
-PRERELEASE 182
+PRERELEASE 183
 PRERELEASE_PATCH 0
\ No newline at end of file