chromeos-dbus-bindings: Add method name generator Create a trivial generator for string constants for each method in the interface. It is assumed that in usage the referring header will enclose an "#include" with the appropriate namespace. BUG=chromium:404505 TEST=New unit test Change-Id: I2cc2a54663e09718b2a50c87d9029bb4bb2b4865 Reviewed-on: https://chromium-review.googlesource.com/215133 Reviewed-by: Alex Vakulenko <[email protected]> Commit-Queue: Paul Stewart <[email protected]> Tested-by: Paul Stewart <[email protected]>