Make Dart_IdentityEqual live up to its sepc and not leak boxing implementation detail. (Reland r275…

runtime/vm/object.cc

 // 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.
 
 #include "vm/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 10465 matching lines @@
     other_type_arguments = instantiated_other.arguments();
   } else {
     other_class = other.type_class();
     other_type_arguments = other.arguments();
   }
   return cls.IsSubtypeOf(type_arguments, other_class, other_type_arguments,
                          bound_error);
 }
 
 
+bool Instance::IsIdenticalTo(const Instance& other) const {
+  if (raw() == other.raw()) return true;
+  if (IsInteger() && other.IsInteger()) {
+    return Equals(other);
+  }
+  if (IsDouble() && other.IsDouble()) {
+    if (Equals(other)) return true;
+    // Check for NaN.
+    const Double& a_double = Double::Cast(*this);
+    const Double& b_double = Double::Cast(other);
+    if (isnan(a_double.value()) && isnan(b_double.value())) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 void Instance::SetNativeField(int index, intptr_t value) const {
   ASSERT(IsValidNativeIndex(index));
   Object& native_fields = Object::Handle(*NativeFieldsAddr());
   if (native_fields.IsNull()) {
     // Allocate backing storage for the native fields.
     const Class& cls = Class::Handle(clazz());
     int num_native_fields = cls.num_native_fields();
     native_fields = TypedData::New(kIntPtrCid, num_native_fields);
     StorePointer(NativeFieldsAddr(), native_fields.raw());
   }
@@ skipping 4540 matching lines @@
   return "_MirrorReference";
 }
 
 
 void MirrorReference::PrintToJSONStream(JSONStream* stream, bool ref) const {
   JSONObject jsobj(stream);
 }
 
 
 }  // namespace dart