[vm] Enable mirrors in product mode. Allows building a product mode SDK.

runtime/vm/flag_list.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 RUNTIME_VM_FLAG_LIST_H_
 #define RUNTIME_VM_FLAG_LIST_H_
 
 // Don't use USING_DBC outside of this file.
 #if defined(TARGET_ARCH_DBC)
 #define USING_DBC true
@@ skipping 52 matching lines @@
   R(disable_alloc_stubs_after_gc, false, bool, false, "Stress testing flag.")  \
   R(disassemble, false, bool, false, "Disassemble dart code.")                 \
   R(disassemble_optimized, false, bool, false, "Disassemble optimized code.")  \
   R(dump_megamorphic_stats, false, bool, false,                                \
     "Dump megamorphic cache statistics")                                       \
   R(dump_symbol_stats, false, bool, false, "Dump symbol table statistics")     \
   P(dwarf_stack_traces, bool, false,                                           \
     "Emit DWARF line number and inlining info"                                 \
     "in dylib snapshots and don't symbolize stack traces.")                    \
   R(enable_asserts, false, bool, false, "Enable assert statements.")           \
-  C(enable_mirrors, false, false, bool, true,                                  \
+  P(enable_mirrors, bool, true,                                                \
     "Disable to make importing dart:mirrors an error.")                        \
   R(enable_type_checks, false, bool, false, "Enable type checks.")             \
   R(error_on_bad_override, false, bool, false,                                 \
     "Report error for bad overrides.")                                         \
   R(error_on_bad_type, false, bool, false,                                     \
     "Report error for malformed types.")                                       \
   P(external_max_size, int, (kWordSize <= 4) ? 512 : 1024,                     \
     "Max total size of external allocations in MB, or 0 for unlimited,"        \
     "e.g: --external_max_size=1024 allows up to 1024MB of externals")          \
   P(fields_may_be_reset, bool, false,                                          \
@@ skipping 91 matching lines @@
   P(verbose_gc_hdr, int, 40, "Print verbose GC header interval.")              \
   R(verify_after_gc, false, bool, false,                                       \
     "Enables heap verification after GC.")                                     \
   R(verify_before_gc, false, bool, false,                                      \
     "Enables heap verification before GC.")                                    \
   D(verify_gc_contains, bool, false,                                           \
     "Enables verification of address contains during GC.")                     \
   D(verify_on_transition, bool, false, "Verify on dart <==> VM.")
 
 #endif  // RUNTIME_VM_FLAG_LIST_H_