Reduce ambiguity in between the record itself, which now stores other
information besides the public key, and its `publicKey` attribute, which
contains an ArrayBuffer of key material.
This model is internal to SignalProtocolStore.
// FREEBIE
Previously we would only clear the publicKey since that was the only attribute,
but now we should delete the entire record. This method is currently only called
from tests.
// FREEBIE
saveIdentityWithAtttributes allows directly setting all properties of an
identity key record. In AccountManager we use it to save our own identity
key after a new registration.
Previously we would remove the existing key first in order to coerce firstUse to
true, but now we can simply set it explicitly, along with a VERIFIED status.
// FREEBIE
This will enforce that all identity record attributes are valid and present
before allowing the record to be saved. This is necessary since we will be
exposing a lower-level method to save an identity with explicit values for
firstUse, nonblockingApproval, and verified status.
Previously we only expected these errors to occur when decrypting prekey
messages, so we need to add handling for them in the case of a normal message.
// FREEBIE
Multiple cases here:
1. setting our own key on registration
1. changing identities from a safety number change dialog
Note that removeIdentityKey runs before saveIdentity, so we'll always end up
with firstUse: true on our own key.
// FREEBIE
saveIdentity is now reponsible for determining firstUse, so we must not remove
the existing key before updating it.
Previously, the implementation provided an extra check against overwritting an
existing key, but that should be done via isTrustedIdentity instead.
// FREEBIE
We can use the same padded plaintext across multiple numbers or attempts rather
than re-creating it every time we encrypt to a particular number.
// FREEBIE
Verified that the Alt+S shortcut isn't installed on new installs, but I
suspect that it won't fix the situation for users who have already
installed older builds, and have the Alt+S shortcut in place.
FREEBIE
