Move ScopedGroupBookmarkActions into bookmarks namespace.

components/bookmarks/browser/scoped_group_bookmark_actions.cc

Index: components/bookmarks/browser/scoped_group_bookmark_actions.cc
diff --git a/components/bookmarks/browser/scoped_group_bookmark_actions.cc b/components/bookmarks/browser/scoped_group_bookmark_actions.cc
index b928ebaa27fc0d2b694ff78728d120550e6d4605..f962e2961d6c79fadb265d92058a49e9d5b819c0 100644
--- a/components/bookmarks/browser/scoped_group_bookmark_actions.cc
+++ b/components/bookmarks/browser/scoped_group_bookmark_actions.cc
@@ -6,6 +6,8 @@
 
 #include "components/bookmarks/browser/bookmark_model.h"
 
+namespace bookmarks {
+
 ScopedGroupBookmarkActions::ScopedGroupBookmarkActions(BookmarkModel* model)
     : model_(model) {
   if (model_)
@@ -16,3 +18,5 @@ ScopedGroupBookmarkActions::~ScopedGroupBookmarkActions() {
   if (model_)
     model_->EndGroupedChanges();
 }
+
+}  // namespace bookmarks