chromeos-dbus-bindings: Add D-Bus signature parser Add a utility for converting a D-Bus signature into the C++ typename equivalent. BUG=chromium:404505 TEST=New unit test Change-Id: I05b51014741f001089dfcbbab6eb1a0b6f96d888 Reviewed-on: https://chromium-review.googlesource.com/216491 Reviewed-by: Paul Stewart <[email protected]> Commit-Queue: Paul Stewart <[email protected]> Tested-by: Paul Stewart <[email protected]>