Implement function proxies (except for their use as constructors).

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index 70ed47be1f4edb17dd08033249d13b00ea273a44..43dada17dfd82f839bfcfbfcf5344ec5c899bc7d 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -3837,7 +3837,16 @@ void JSBuiltinsObject::set_javascript_builtin_code(Builtins::JavaScript id,
 
 
 ACCESSORS(JSProxy, handler, Object, kHandlerOffset)
-ACCESSORS(JSProxy, padding, Object, kPaddingOffset)
+ACCESSORS(JSFunctionProxy, call_trap, Object, kCallTrapOffset)
+ACCESSORS(JSFunctionProxy, construct_trap, Object, kConstructTrapOffset)
+
+
+void JSProxy::InitializeBody(int object_size, Object* value) {
+  ASSERT(!value->IsHeapObject() || !GetHeap()->InNewSpace(value));
+  for (int offset = kHeaderSize; offset < object_size; offset += kPointerSize) {
+    WRITE_FIELD(this, offset, value);
+  }
+}
 
 
 ACCESSORS(JSWeakMap, table, ObjectHashTable, kTableOffset)