A bunch of remaining parts of extension content verification (Reland)

extensions/common/file_util.h

Index: extensions/common/file_util.h
diff --git a/extensions/common/file_util.h b/extensions/common/file_util.h
index 597d085bef0a7c935524041b9236ad854663554e..32c370ee96bdbb9ed15a31896920bd02812ac2e1 100644
--- a/extensions/common/file_util.h
+++ b/extensions/common/file_util.h
@@ -122,6 +122,10 @@ std::map<std::string, std::string>* LoadMessageBundleSubstitutionMap(
     const std::string& extension_id,
     const std::string& default_locale);
 
+// Helper functions for getting paths for files used in content verification.
+base::FilePath GetVerifiedContentsPath(const base::FilePath& extension_path);
+base::FilePath GetComputedHashesPath(const base::FilePath& extension_path);
+
 }  // namespace file_util
 }  // namespace extensions