Change a result code ENUM value to help diagnose unexpected histogram data

chrome/common/chrome_result_codes.h

Index: chrome/common/chrome_result_codes.h
diff --git a/chrome/common/chrome_result_codes.h b/chrome/common/chrome_result_codes.h
index 045edd97423a24535f72d033d250235d912791b6..b6f7a839bf81d1d8319f83418ae92241642cc98a 100644
--- a/chrome/common/chrome_result_codes.h
+++ b/chrome/common/chrome_result_codes.h
@@ -72,9 +72,15 @@ enum ResultCode {
   // running browser.
   RESULT_CODE_NORMAL_EXIT_PROCESS_NOTIFIED,
 
+  // A dummy value we should not use. See crbug.com/152285.
+  RESULT_CODE_NOTUSED_1,
+
   // Failed to install an item from the webstore when the kInstallFromWebstore
   // command line flag was present.
-  RESULT_CODE_INSTALL_FROM_WEBSTORE_ERROR,
+  RESULT_CODE_INSTALL_FROM_WEBSTORE_ERROR_2,
+
+  // A dummy value we should not use. See crbug.com/152285.
+  RESULT_CODE_NOTUSED_2,
 
   // Last return code (keep this last).
   RESULT_CODE_CHROME_LAST_CODE,