Implement get trap for proxies.

src/handles.cc

Index: src/handles.cc
diff --git a/src/handles.cc b/src/handles.cc
index 326de8637ad8fa085dff02cfa8eb350ef7a365f4..3d5ac20613a997938ea6bddb967435ba0e46f9ca 100644
--- a/src/handles.cc
+++ b/src/handles.cc
@@ -362,6 +362,17 @@ Handle<Object> GetProperty(Handle<JSObject> obj,
 
 
 Handle<Object> GetProperty(Handle<Object> obj,
+                           const char* name,
+                           LookupResult* result) {
+  Isolate* isolate = Isolate::Current();
+  Handle<String> str = isolate->factory()->LookupAsciiSymbol(name);
+  PropertyAttributes attributes;
+  CALL_HEAP_FUNCTION(
+      isolate, obj->GetProperty(*obj, result, *str, &attributes), Object);
+}
+
+
+Handle<Object> GetProperty(Handle<Object> obj,
                            Handle<Object> key) {
   Isolate* isolate = Isolate::Current();
   CALL_HEAP_FUNCTION(isolate,