Support new optional parameter syntax (issue 4289)

compiler/java/com/google/dart/compiler/parser/ParserErrorCode.java

Index: compiler/java/com/google/dart/compiler/parser/ParserErrorCode.java
===================================================================
--- compiler/java/com/google/dart/compiler/parser/ParserErrorCode.java	(revision 10825)
+++ compiler/java/com/google/dart/compiler/parser/ParserErrorCode.java	(working copy)
@@ -22,6 +22,7 @@
   BUILT_IN_IDENTIFIER_AS_TYPE_NAME("Built-in identifier cannot be used as type name"),
   BUILT_IN_IDENTIFIER_AS_TYPEDEF_NAME("Built-in identifier can not be used as type alias name"),
   BUILT_IN_IDENTIFIER_AS_TYPE_VARIABLE_NAME("Built-in identifier can not be used as type variable name"),
+  CANNOT_MIX_OPTIONAL_AND_NAMED_PARAMETERS("Cannot mix both optional and named parameters in the same function"),
   CATCH_OR_FINALLY_EXPECTED("catch or finally clause expected."),
   CONTINUE_IN_CASE_MUST_HAVE_LABEL("'continue' in case statement must have a label as a target."),
   CONTINUE_OUTSIDE_OF_LOOP("'continue' used outside of loop or case statement"),
@@ -69,6 +70,8 @@
   EXTERNAL_ONLY_METHOD("Only a top-level function, a method, a getter, a setter or an non-redirecting constructor can be specified as external"),
   EXTERNAL_METHOD_BODY("External methods cannot have body"),
   EXTERNAL_ABSTRACT("External methods cannot be abstract"),
+  INVALID_SEPARATOR_FOR_NAMED("Use ':' between a named parameter and its value"),
+  INVALID_SEPARATOR_FOR_OPTIONAL("Use '=' between an optional parameter and its value"),
   // TODO(zundel): this error message is out of date
   NATIVE_ONLY_CLASS("Native keyword can be specified only for classes"),
   NATIVE_ONLY_CORE_LIB("Native keyword can be used only in corelib"),
@@ -95,7 +98,8 @@
   LABEL_NOT_FOLLOWED_BY_CASE_OR_DEFAULT("Label not followed by 'case', 'default', or statement"),
   LOCAL_CANNOT_BE_STATIC("Local function cannot be static"),
   MISSING_FUNCTION_NAME(ErrorSeverity.WARNING, "a function name is required for a declaration"),
-  MISSING_NAMED_PARAMETER_END("Expected ']' to close the list of named parameters"),
+  MISSING_NAMED_PARAMETER_END("Expected '}' to close the list of named parameters"),
+  MISSING_OPTIONAL_PARAMETER_END("Expected ']' to close the list of optional parameters"),
   NAMED_PARAMETER_NOT_ALLOWED("Named parameter is not allowed for operator or setter method"),
   NO_SPACE_AFTER_PLUS("Cannot have space between plus and numeric literal"),
   NO_SOUP_FOR_YOU("Too many errors"),