Some easy linked_ptr removal from extensions/common/

extensions/common/message_bundle.h

Index: extensions/common/message_bundle.h
diff --git a/extensions/common/message_bundle.h b/extensions/common/message_bundle.h
index 9c0bde79a303447185c1b7a33eff3922945f5368..d0e3746b86208fcd817ef2b9d3734550f730702f 100644
--- a/extensions/common/message_bundle.h
+++ b/extensions/common/message_bundle.h
@@ -8,11 +8,10 @@
 #include <stddef.h>
 
 #include <map>
+#include <memory>
 #include <string>
 #include <vector>
 
-#include "base/memory/linked_ptr.h"
-
 namespace base {
 class DictionaryValue;
 class Value;
@@ -24,8 +23,8 @@ namespace extensions {
 // locale does not provide are pulled from the default locale.
 class MessageBundle {
  public:
-  typedef std::map<std::string, std::string> SubstitutionMap;
-  typedef std::vector<linked_ptr<base::DictionaryValue> > CatalogVector;
+  using SubstitutionMap = std::map<std::string, std::string>;
+  using CatalogVector = std::vector<std::unique_ptr<base::DictionaryValue>>;
 
   // JSON keys of interest for messages file.
   static const char kContentKey[];