Check Member<T> validity for stack allocated objects.

tools/clang/blink_gc_plugin/RecordInfo.cpp

Index: tools/clang/blink_gc_plugin/RecordInfo.cpp
diff --git a/tools/clang/blink_gc_plugin/RecordInfo.cpp b/tools/clang/blink_gc_plugin/RecordInfo.cpp
index 6e591a5484584987a9e326377e29be0641772a88..3749594333c114bfa4a1895840a0712b10a9d813 100644
--- a/tools/clang/blink_gc_plugin/RecordInfo.cpp
+++ b/tools/clang/blink_gc_plugin/RecordInfo.cpp
@@ -186,6 +186,10 @@ bool RecordInfo::IsEagerlyFinalized() {
   return is_eagerly_finalized_;
 }
 
+bool RecordInfo::HasDefinition() {
+  return record_->hasDefinition();
+}
+
 RecordInfo* RecordCache::Lookup(CXXRecordDecl* record) {
   // Ignore classes annotated with the GC_PLUGIN_IGNORE macro.
   if (!record || Config::IsIgnoreAnnotated(record))