Rewrite Error.prototype.toString in C++.

src/isolate.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ISOLATE_H_
 #define V8_ISOLATE_H_
 
 #include <queue>
 #include <set>
 
 #include "include/v8-debug.h"
 #include "src/allocation.h"
 #include "src/assert-scope.h"
 #include "src/base/atomicops.h"
 #include "src/builtins.h"
 #include "src/cancelable-task.h"
 #include "src/contexts.h"
 #include "src/date.h"
 #include "src/execution.h"
 #include "src/frames.h"
 #include "src/futex-emulation.h"
 #include "src/global-handles.h"
 #include "src/handles.h"
 #include "src/hashmap.h"
 #include "src/heap/heap.h"
+#include "src/messages.h"
 #include "src/optimizing-compile-dispatcher.h"
 #include "src/regexp-stack.h"
 #include "src/runtime/runtime.h"
 #include "src/runtime-profiler.h"
 #include "src/zone.h"
 
 namespace v8 {
 
 namespace base {
 class RandomNumberGenerator;
@@ skipping 951 matching lines @@
     return date_cache_;
   }
 
   void set_date_cache(DateCache* date_cache) {
     if (date_cache != date_cache_) {
       delete date_cache_;
     }
     date_cache_ = date_cache;
   }
 
+  ErrorToStringHelper* error_tostring_helper() {
+    return &error_tostring_helper_;
+  }
+
   Map* get_initial_js_array_map(ElementsKind kind,
                                 Strength strength = Strength::WEAK);
 
   static const int kArrayProtectorValid = 1;
   static const int kArrayProtectorInvalid = 0;
 
   bool IsFastArrayConstructorPrototypeChainIntact();
 
   // On intent to set an element in object, make sure that appropriate
   // notifications occur if the set is on the elements of the array or
@@ skipping 282 matching lines @@
   ThreadManager* thread_manager_;
   RuntimeState runtime_state_;
   Builtins builtins_;
   bool has_installed_extensions_;
   unibrow::Mapping<unibrow::Ecma262UnCanonicalize> jsregexp_uncanonicalize_;
   unibrow::Mapping<unibrow::CanonicalizationRange> jsregexp_canonrange_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize>
       regexp_macro_assembler_canonicalize_;
   RegExpStack* regexp_stack_;
   DateCache* date_cache_;
+  ErrorToStringHelper error_tostring_helper_;
   unibrow::Mapping<unibrow::Ecma262Canonicalize> interp_canonicalize_mapping_;
   CallInterfaceDescriptorData* call_descriptor_data_;
   base::RandomNumberGenerator* random_number_generator_;
   // TODO(hpayer): Remove the following store buffer addresses.
   uintptr_t* store_buffer_hash_set_1_address_;
   uintptr_t* store_buffer_hash_set_2_address_;
 
   // Whether the isolate has been created for snapshotting.
   bool serializer_enabled_;
 
@@ skipping 290 matching lines @@
   }
 
   EmbeddedVector<char, 128> filename_;
   FILE* file_;
   int scope_depth_;
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_ISOLATE_H_