Handlify Object::GetPrototype and (most) callers.

src/objects.h

Index: src/objects.h
diff --git a/src/objects.h b/src/objects.h
index bc5c196bff48187b6400cf0e758611b549d105ee..fca6f60b910a57b4baedf5430bbc9da7f0e11514 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1575,8 +1575,8 @@ class Object : public MaybeObject {
       uint32_t index);
 
   // Return the object's prototype (might be Heap::null_value()).
-  Object* GetPrototype(Isolate* isolate);
   static Handle<Object> GetPrototype(Isolate* isolate, Handle<Object> object);
+
   Map* GetMarkerMap(Isolate* isolate);
 
   // Returns the permanent hash code associated with this object. May return
@@ -1625,6 +1625,8 @@ class Object : public MaybeObject {
   static const int kHeaderSize = 0;  // Object does not take up any space.
 
  private:
+  Object* GetPrototype(Isolate* isolate);
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(Object);
 };