Avoid UTF-8 decoding in num.toString.

runtime/vm/object.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_OBJECT_H_
 #define VM_OBJECT_H_
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 244 matching lines @@
   static intptr_t tags_offset() { return OFFSET_OF(RawObject, tags_); }
 
   // Class testers.
 #define DEFINE_CLASS_TESTER(clazz)                                             \
   virtual bool Is##clazz() const { return false; }
   CLASS_LIST_FOR_HANDLES(DEFINE_CLASS_TESTER);
 #undef DEFINE_CLASS_TESTER
 
   bool IsNull() const { return raw_ == null_; }
 
+  // Matches Object.toString on instances (except String::ToCString, bug 20583).
   virtual const char* ToCString() const {
     if (IsNull()) {
       return "null";
     } else {
       return "Object";
     }
   }
 
   void PrintJSON(JSONStream* stream, bool ref = true) const;
 
@@ skipping 4722 matching lines @@
 
   static RawMixinAppType* New();
 
   FINAL_HEAP_OBJECT_IMPLEMENTATION(MixinAppType, AbstractType);
   friend class Class;
 };
 
 
 class Number : public Instance {
  public:
-  // TODO(iposva): Fill in a useful Number interface.
+  // TODO(iposva): Add more useful Number methods.
+  RawString* ToString(Heap::Space space) const;
 
  private:
   OBJECT_IMPLEMENTATION(Number, Instance);
   friend class Class;
 };
 
 
 class Integer : public Number {
  public:
   static RawInteger* New(const String& str, Heap::Space space = Heap::kNew);
@@ skipping 2301 matching lines @@
 
 
 RawObject* MegamorphicCache::GetTargetFunction(const Array& array,
                                                intptr_t index) {
   return array.At((index * kEntryLength) + kTargetFunctionIndex);
 }
 
 }  // namespace dart
 
 #endif  // VM_OBJECT_H_