Remove sender from Applyable. (#5129)

substrate/primitives/runtime/src/traits.rs

@@ -879,18 +879,12 @@ impl SignedExtension for () {
 /// Also provides information on to whom this information is attributable and an index that allows
 /// each piece of attributable information to be disambiguated.
 pub trait Applyable: Sized + Send + Sync {
-	/// ID of the account that is responsible for this piece of information (sender).
-	type AccountId: Member + MaybeDisplay;
-
 	/// Type by which we can dispatch. Restricts the `UnsignedValidator` type.
 	type Call;
 
 	/// An opaque set of information attached to the transaction.
 	type DispatchInfo: Clone;
 
-	/// Returns a reference to the sender if any.
-	fn sender(&self) -> Option<&Self::AccountId>;
-
 	/// Checks to see if this is a valid *transaction*. It returns information on it if so.
 	fn validate<V: ValidateUnsigned<Call=Self::Call>>(
 		&self,