The U2F Soft Token, due to its usage of NSS, has to have const values be
marked non-const - but no such limitation should exist for other implementations
of U2F, so this patch moves the const_cast-ing from the U2FTokenManager-level
down to the U2FSoftTokenManager, where it is actually necessary.
Credit to Axel Nennker for this patch.
MozReview-Commit-ID: Kw6zfTDI3GL
--HG--
extra : rebase_source : 90e31e2da9e021043509653a476ddaae03078e55
Takes functionality that was in the WebAuthentication class that now
needs to be handled by the parent process, and moves it to the
U2FTokenManager singleton class. U2FTokenManager is created on the
PBackground thread during the first WebAuthn transaction, and manages
hardware access and transaction management for the lifetime of the
browser session. Patch also adds parent classes for WebAuthn IPC
protocol.
MozReview-Commit-ID: EnhgUTPdlMZ