WIP: Create a public v8::DictionarySchema API for bulk reads from dict objects.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index b4449f01318de8d2488979c33e134cee2a14c0eb..bef43a30befe3c0bc47a039879aae17423450c17 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -80,6 +80,7 @@
 //       - BytecodeArray
 //       - FixedArray
 //         - DescriptorArray
+//         - DictionarySchema
 //         - FrameArray
 //         - HashTable
 //           - Dictionary
@@ -1007,6 +1008,7 @@ template <class C> inline bool Is(Object* obj);
   V(JSModuleNamespace)           \
   V(Map)                         \
   V(DescriptorArray)             \
+  V(DictionarySchema)            \
   V(FrameArray)                  \
   V(TransitionArray)             \
   V(FeedbackMetadata)            \
@@ -3236,6 +3238,16 @@ class DescriptorArray: public FixedArray {
   DISALLOW_IMPLICIT_CONSTRUCTORS(DescriptorArray);
 };
 
+// A list of keys expected to be searched in "dictionary-like" objects.
+// See v8::DictionarySchema.
+class DictionarySchema : public FixedArray {
+ public:
+  static Handle<DictionarySchema> New(Isolate* isolate, int size);
+  DECLARE_CAST(DictionarySchema);
+
+ private:
+  DISALLOW_IMPLICIT_CONSTRUCTORS(DictionarySchema);
+};
 
 enum SearchMode { ALL_ENTRIES, VALID_ENTRIES };