Blink GC plugin: look for checked namespaces within the list of namespaces.

tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp

Index: tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp
diff --git a/tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp b/tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp
index 4b023c3a9d46e7ffe5b7648f14cf09e7fdc38a1b..31a83e8f2ddbf9054228b86344ac9785510dfca7 100644
--- a/tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp
+++ b/tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp
@@ -1060,12 +1060,14 @@ class BlinkGCPluginConsumer : public ASTConsumer {
     DeclContext* context = info->record()->getDeclContext();
     if (context->isRecord())
       return InCheckedNamespace(cache_.Lookup(context));
-    if (context->isNamespace()) {
-      const NamespaceDecl* decl = dyn_cast<NamespaceDecl>(context);
+    while (context->isNamespace()) {
+      NamespaceDecl* decl = dyn_cast<NamespaceDecl>(context);
       if (decl->isAnonymousNamespace())
         return false;
-      return options_.checked_namespaces.find(decl->getNameAsString()) !=
-          options_.checked_namespaces.end();
+      if (options_.checked_namespaces.find(decl->getNameAsString()) !=
+          options_.checked_namespaces.end())
+        return true;
+      context = decl->getDeclContext();
     }
     return false;
   }