Remove base::ScopedPtrHashMap from components/prefs/.

components/prefs/pref_value_map.h

Index: components/prefs/pref_value_map.h
diff --git a/components/prefs/pref_value_map.h b/components/prefs/pref_value_map.h
index 011b2a472688064d333adb47111e54dd07ac3032..b0ffbd15fdda3ef1900cf507aec5bd4768d10a24 100644
--- a/components/prefs/pref_value_map.h
+++ b/components/prefs/pref_value_map.h
@@ -7,9 +7,9 @@
 
 #include <memory>
 #include <string>
+#include <unordered_map>
 #include <vector>
 
-#include "base/containers/scoped_ptr_hash_map.h"
 #include "base/macros.h"
 #include "components/prefs/base_prefs_export.h"
 
@@ -20,7 +20,7 @@ class Value;
 // A generic string to value map used by the PrefStore implementations.
 class COMPONENTS_PREFS_EXPORT PrefValueMap {
  public:
-  using Map = base::ScopedPtrHashMap<std::string, std::unique_ptr<base::Value>>;
+  using Map = std::unordered_map<std::string, std::unique_ptr<base::Value>>;
   using iterator = Map::iterator;
   using const_iterator = Map::const_iterator;