Morph the APIs for Node, ParentNode, and Element closer to the specs

sky/engine/tonic/dart_wrappable.cc

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "sky/engine/config.h"
 #include "sky/engine/tonic/dart_wrappable.h"
 
 #include "sky/engine/tonic/dart_class_library.h"
 #include "sky/engine/tonic/dart_error.h"
 #include "sky/engine/tonic/dart_state.h"
@@ skipping 32 matching lines @@
 void DartWrappable::FinalizeDartWrapper(void* isolate_callback_data,
                                         Dart_WeakPersistentHandle wrapper,
                                         void* peer) {
   DartWrappable* wrappable = reinterpret_cast<DartWrappable*>(peer);
   wrappable->dart_wrapper_ = nullptr;
   const DartWrapperInfo& info = wrappable->GetDartWrapperInfo();
   info.deref_object(wrappable);  // Balanced in CreateDartWrapper.
 }
 
 DartWrappable* DartConverterWrappable::FromDart(Dart_Handle handle) {
-  intptr_t* peer = 0;
+  intptr_t peer = 0;
   Dart_Handle result =
-      Dart_GetNativeInstanceField(handle, DartWrappable::kPeerIndex, peer);
+      Dart_GetNativeInstanceField(handle, DartWrappable::kPeerIndex, &peer);
   if (Dart_IsError(result))
     return nullptr;
   return reinterpret_cast<DartWrappable*>(peer);
 }
 
 DartWrappable* DartConverterWrappable::FromArguments(Dart_NativeArguments args,
                                                      int index,
                                                      Dart_Handle& exception) {
   intptr_t native_fields[DartWrappable::kNumberOfNativeFields];
   Dart_Handle result = Dart_GetNativeFieldsOfArgument(
@@ skipping 16 matching lines @@
       args, index, DartWrappable::kNumberOfNativeFields, native_fields);
   if (Dart_IsError(result)) {
     exception = Dart_NewStringFromCString(DartError::kInvalidArgument);
     return nullptr;
   }
   return reinterpret_cast<DartWrappable*>(
       native_fields[DartWrappable::kPeerIndex]);
 }
 
 }  // namespace blink