Add interceptor support for symbols

test/cctest/test-debug.cc

Index: test/cctest/test-debug.cc
diff --git a/test/cctest/test-debug.cc b/test/cctest/test-debug.cc
index 433190750461998d204148f95f4092312ae638b1..6bc8a5e33a5b43b692a94927129893442df99b79 100644
--- a/test/cctest/test-debug.cc
+++ b/test/cctest/test-debug.cc
@@ -4270,9 +4270,10 @@ static void IndexedEnum(const v8::PropertyCallbackInfo<v8::Array>& info) {
 }
 
 
-static void NamedGetter(v8::Local<v8::String> name,
+static void NamedGetter(v8::Local<v8::Name> name,
                         const v8::PropertyCallbackInfo<v8::Value>& info) {
-  v8::String::Utf8Value n(name);
+  if (name->IsSymbol()) return;
+  v8::String::Utf8Value n(v8::Local<v8::String>::Cast(name));
   if (strcmp(*n, "a") == 0) {
     info.GetReturnValue().Set(v8::String::NewFromUtf8(info.GetIsolate(), "AA"));
     return;