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 ca8b092e83a74d003027d68eb2218cacefeef972..1f7faba808fb1fa42f296d1871eb947031caed51 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 {
 
 // The magic header in PReg files: ASCII "PReg" + version (0x0001).
@@ -31,7 +34,8 @@ extern const char kPRegFileHeader[8];
 // 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