Add google_update::GetUntrustedDataValueFromTag()

chrome/installer/util/google_update_util.h

Index: chrome/installer/util/google_update_util.h
diff --git a/chrome/installer/util/google_update_util.h b/chrome/installer/util/google_update_util.h
index 30d77e95b6519f1af197fd9e86225440473ce2fd..d72cd686eb1ea5f08b8fbffe9f53dccb11268484 100644
--- a/chrome/installer/util/google_update_util.h
+++ b/chrome/installer/util/google_update_util.h
@@ -27,6 +27,12 @@ bool UninstallGoogleUpdate(bool system_install);
 // contains non-printable characters.
 std::string GetUntrustedDataValue(const std::string& key);
 
+// Returns the value corresponding to |key| in untrusted data passed from
+// |tag|.  Returns an empty string if |key| is absent or if its value

[grt (UTC plus 2), 2014/03/03 15:18:26]

please document the expected format of |tag|.

[jackhou1, 2014/03/04 00:56:28]

Done.

+// contains non-printable characters.
+std::string GetUntrustedDataValueFromTag(const std::string& tag,
+                                         const std::string& key);
+
 }  // namespace google_update
 
 #endif  // CHROME_INSTALLER_UTIL_GOOGLE_UPDATE_UTIL_H_