Hide MirroredCompilationErrror behind a flag until post-1.0.

runtime/vm/symbols.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_SYMBOLS_H_
 #define VM_SYMBOLS_H_
 
 #include "vm/object.h"
 #include "vm/snapshot_ids.h"
 
@@ skipping 219 matching lines @@
   V(FormatException, "FormatException")                                        \
   V(UnsupportedError, "UnsupportedError")                                      \
   V(StackOverflowError, "StackOverflowError")                                  \
   V(OutOfMemoryError, "OutOfMemoryError")                                      \
   V(InternalError, "InternalError")                                            \
   V(NullThrownError, "NullThrownError")                                        \
   V(IsolateSpawnException, "IsolateSpawnException")                            \
   V(IsolateUnhandledException, "IsolateUnhandledException")                    \
   V(JavascriptIntegerOverflowError, "_JavascriptIntegerOverflowError")         \
   V(MirroredCompilationError, "MirroredCompilationError")                      \
-  V(MirroredUncaughtExceptionError, "MirroredUncaughtExceptionError")          \
   V(_setupFullStackTrace, "_setupFullStackTrace")                              \
   V(BooleanExpression, "boolean expression")                                   \
   V(Malformed, "malformed")                                                    \
   V(InstanceOf, "InstanceOf")                                                  \
   V(MegamorphicMiss, "megamorphic_miss")                                       \
   V(CommaSpace, ", ")                                                          \
   V(ColonSpace, ": ")                                                          \
   V(RParenArrow, ") => ")                                                      \
   V(SpaceExtendsSpace, " extends ")                                            \
   V(SwitchExpr, ":switch_expr")                                                \
@@ skipping 239 matching lines @@
   friend class SnapshotReader;
   friend class SnapshotWriter;
   friend class ApiMessageReader;
 
   DISALLOW_COPY_AND_ASSIGN(Symbols);
 };
 
 }  // namespace dart
 
 #endif  // VM_SYMBOLS_H_