Add min and max to ExecutionMode enum.

components/chrome_cleaner/public/constants/constants.h

Index: components/chrome_cleaner/public/constants/constants.h
diff --git a/components/chrome_cleaner/public/constants/constants.h b/components/chrome_cleaner/public/constants/constants.h
index d31232ab52bbd7070e4edd035bbbda09cb5e9feb..9ca9a5d317c3278047b7952e19cb37ddc8d84c6a 100644
--- a/components/chrome_cleaner/public/constants/constants.h
+++ b/components/chrome_cleaner/public/constants/constants.h
@@ -114,6 +114,9 @@ enum class ExecutionMode {
   // to the user and logs will only be uploaded if the user opted into Extended
   // Safe Browsing Reporting v2.
   kPostRebootValidation = 3,
+
+  // Auxiliary enumerator for range checking.
+  kNumValues,
 };
 
 }  // namespace chrome_cleaner