Add UMA histograms for policy loading.

chrome/browser/policy/preg_parser_win.h

Index: chrome/browser/policy/preg_parser_win.h
diff --git a/chrome/browser/policy/preg_parser_win.h b/chrome/browser/policy/preg_parser_win.h
index 09427e6a04e8daa915b1db4799dbbb00ba14c82d..1c0b9b0ba2906e214b62bf057147e8f9469ad1a1 100644
--- a/chrome/browser/policy/preg_parser_win.h
+++ b/chrome/browser/policy/preg_parser_win.h
@@ -21,6 +21,9 @@ class FilePath;
 }
 
 namespace policy {
+
+class PolicyLoadStatusSample;
+
 namespace preg_parser {
 
 // Reads the PReg file at |file_path| and writes the registry data to |dict|.
@@ -28,7 +31,8 @@ namespace preg_parser {
 // everything else gets ignored.
 bool ReadFile(const base::FilePath& file_path,
               const string16& root,
-              base::DictionaryValue* dict);
+              base::DictionaryValue* dict,
+              PolicyLoadStatusSample* status);
 
 }  // namespace preg_parser
 }  // namespace policy