This adds a list of `Procedure`s to `ExtensionTypeDeclaration`. This is
meant to model representation fields and combined member signatures
computed from inherited non-extension type members.
These are not meant to be handled by the backends. The combined
member signature can be the interface target of an `InstanceInvocation`
expression but will always have a `.memberSignatureOrigin` value from
one of the original class members.
TEST=existing
Change-Id: I87768ed75a3c7126b0a30f8ccf06e46678c56db6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/330301
Reviewed-by: Alexander Markov <alexmarkov@google.com>
Reviewed-by: Srujan Gaddam <srujzs@google.com>
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Johnni Winther <johnniwinther@google.com>
Johnni Winther
f87142fdc2