Add "checked mode compile time error" type to analysis server API.

pkg/analysis_server/lib/src/generated_protocol.dart

Index: pkg/analysis_server/lib/src/generated_protocol.dart
diff --git a/pkg/analysis_server/lib/src/generated_protocol.dart b/pkg/analysis_server/lib/src/generated_protocol.dart
index e35ef59061ad28afe4f4b4d536a4ce6ab5296dbc..5b97b187e9138efbde54c7367e15e2cea4259923 100644
--- a/pkg/analysis_server/lib/src/generated_protocol.dart
+++ b/pkg/analysis_server/lib/src/generated_protocol.dart
@@ -4755,6 +4755,7 @@ class AnalysisErrorSeverity {
  *
  * enum {
  *   ANGULAR
+ *   CHECKED_MODE_COMPILE_TIME_ERROR
  *   COMPILE_TIME_ERROR
  *   HINT
  *   POLYMER
@@ -4767,6 +4768,8 @@ class AnalysisErrorSeverity {
 class AnalysisErrorType {
   static const ANGULAR = const AnalysisErrorType._("ANGULAR");
 
+  static const CHECKED_MODE_COMPILE_TIME_ERROR = const AnalysisErrorType._("CHECKED_MODE_COMPILE_TIME_ERROR");
+
   static const COMPILE_TIME_ERROR = const AnalysisErrorType._("COMPILE_TIME_ERROR");
 
   static const HINT = const AnalysisErrorType._("HINT");
@@ -4789,6 +4792,8 @@ class AnalysisErrorType {
     switch (name) {
       case "ANGULAR":
         return ANGULAR;
+      case "CHECKED_MODE_COMPILE_TIME_ERROR":
+        return CHECKED_MODE_COMPILE_TIME_ERROR;
       case "COMPILE_TIME_ERROR":
         return COMPILE_TIME_ERROR;
       case "HINT":