content: Use stl utilities from the base namespace

content/browser/plugin_private_storage_helper.cc

Index: content/browser/plugin_private_storage_helper.cc
diff --git a/content/browser/plugin_private_storage_helper.cc b/content/browser/plugin_private_storage_helper.cc
index d7c6228a294541d4c7bd67ad308f60d6791f9640..3d241ea36b5e0eb0ab8fe2b6bc47c7ebb6c021c7 100644
--- a/content/browser/plugin_private_storage_helper.cc
+++ b/content/browser/plugin_private_storage_helper.cc
@@ -395,7 +395,7 @@ void ClearPluginPrivateDataOnFileTaskRunner(
   // If a specific origin is provided, then check that it is in the list
   // returned and remove all the other origins.
   if (!storage_origin.is_empty()) {
-    if (!ContainsKey(origins, storage_origin)) {
+    if (!base::ContainsKey(origins, storage_origin)) {
       // Nothing matches, so nothing to do.
       callback.Run();
       return;