bookmarks: Move bookmark_pasteboard_helper_mac functions into 'bookmarks' namespace.

components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm

Index: components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm
diff --git a/components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm b/components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm
index 204e463b1afbbcaf0e4cfc3e1cfdcb3b3265ee9a..7f390604a31769bfb6f4e9dde309eddadb7a903d 100644
--- a/components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm
+++ b/components/bookmarks/browser/bookmark_pasteboard_helper_mac.mm
@@ -11,11 +11,11 @@
 #include "components/bookmarks/browser/bookmark_node.h"
 #include "ui/base/clipboard/clipboard.h"
 
-using bookmarks::BookmarkNodeData;
-
 NSString* const kBookmarkDictionaryListPboardType =
     @"BookmarkDictionaryListPboardType";
 
+namespace bookmarks {
+
 namespace {
 
 // An unofficial standard pasteboard title type to be provided alongside the
@@ -331,3 +331,5 @@ bool PasteboardContainsBookmarks(ui::ClipboardType type) {
                                 nil];
   return [pb availableTypeFromArray:availableTypes] != nil;
 }
+
+}  // namespace bookmarks