Make members of Singleton<T> private and only visible to the singleton type.

base/path_service.cc

Index: base/path_service.cc
diff --git a/base/path_service.cc b/base/path_service.cc
index 4381998b4791ac3d504bff872a918ff0052b5ff4..56ce5fa4336a6e3830c85487de9187dc1760506e 100644
--- a/base/path_service.cc
+++ b/base/path_service.cc
@@ -13,9 +13,9 @@
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/hash_tables.h"
+#include "base/lazy_instance.h"
 #include "base/lock.h"
 #include "base/logging.h"
-#include "base/singleton.h"
 
 namespace base {
   bool PathProvider(int key, FilePath* result);
@@ -118,8 +118,10 @@ struct PathData {
   }
 };
 
+static base::LazyInstance<PathData> g_path_data(base::LINKER_INITIALIZED);
+
 static PathData* GetPathData() {
-  return Singleton<PathData>::get();
+  return g_path_data.Pointer();
 }
 
 }  // namespace