Support proposal cancellation from runtime.

bin/node/runtime/src/lib.rs

@@ -493,6 +493,13 @@ impl pallet_democracy::Trait for Runtime {
 	type FastTrackVotingPeriod = FastTrackVotingPeriod;
 	// To cancel a proposal which has been passed, 2/3 of the council must agree to it.
 	type CancellationOrigin = pallet_collective::EnsureProportionAtLeast<_2, _3, AccountId, CouncilCollective>;
+	// To cancel a proposal before it has been passed, the technical committee must be unanimous or
+	// Root must agree.
+	type CancelProposalOrigin = EnsureOneOf<
+		AccountId,
+		EnsureRoot<AccountId>,
+		pallet_collective::EnsureProportionAtLeast<_1, _1, AccountId, TechnicalCollective>,
+	>;
 	// Any single technical committee member may veto a coming council proposal, however they can
 	// only do it once and it lasts only for the cooloff period.
 	type VetoOrigin = pallet_collective::EnsureMember<AccountId, TechnicalCollective>;

bin/node/runtime/src/weights/pallet_democracy.rs

@@ -73,6 +73,10 @@ impl pallet_democracy::WeightInfo for WeightInfo {
 			.saturating_add(DbWeight::get().reads(2 as Weight))
 			.saturating_add(DbWeight::get().writes(2 as Weight))
 	}
+	fn cancel_proposal() -> Weight {
+		(20431000 as Weight)
+			.saturating_add(DbWeight::get().writes(1 as Weight))
+	}
 	fn cancel_referendum() -> Weight {
 		(20431000 as Weight)
 			.saturating_add(DbWeight::get().writes(1 as Weight))