Restructure parser error handling and recovery.

pkg/dart_parser/lib/src/error_kind.dart

Index: pkg/dart_parser/lib/src/error_kind.dart
diff --git a/pkg/dart_parser/lib/src/error_kind.dart b/pkg/dart_parser/lib/src/error_kind.dart
index f4df727e43e7e4a149c708e1dd68309c493858f0..baaef155cb1efac10ef45d96eff5c2b36d7c3184 100644
--- a/pkg/dart_parser/lib/src/error_kind.dart
+++ b/pkg/dart_parser/lib/src/error_kind.dart
@@ -7,10 +7,19 @@ library dart_parser.error_kind;
 enum ErrorKind {
   EmptyNamedParameterList,
   EmptyOptionalParameterList,
+  ExpectedBlockToSkip,
   ExpectedBody,
+  ExpectedButGot,
+  ExpectedClassBody,
+  ExpectedClassBodyToSkip,
+  ExpectedDeclaration,
+  ExpectedExpression,
+  ExpectedFunctionBody,
   ExpectedHexDigit,
+  ExpectedIdentifier,
   ExpectedOpenParens,
   ExpectedString,
+  ExpectedType,
   ExtraneousModifier,
   ExtraneousModifierReplace,
   InvalidAwaitFor,
@@ -21,6 +30,7 @@ enum ErrorKind {
   MissingExponent,
   PositionalParameterWithEquals,
   RequiredParameterWithDefault,
+  UnexpectedToken,
   UnmatchedToken,
   UnsupportedPrefixPlus,
   UnterminatedComment,