Refactor sr-api to not depend on client anymore (#4086)

* Refactor sr-api to not depend on client anymore

* Fix benches

* Apply suggestions from code review

Co-Authored-By: Tomasz Drwięga <tomusdrw@users.noreply.github.com>

* Apply suggestions from code review

substrate/srml/contracts/rpc/runtime-api/Cargo.toml

@@ -5,7 +5,7 @@ authors = ["Parity Technologies <admin@parity.io>"]
 edition = "2018"
 
 [dependencies]
-client = { package = "substrate-client", path = "../../../../core/client", default-features = false }
+sr-api = { path = "../../../../core/sr-api", default-features = false }
 codec = { package = "parity-scale-codec", version = "1.0.0", default-features = false, features = ["derive"] }
 rstd = { package = "sr-std", path = "../../../../core/sr-std", default-features = false }
 serde = { version = "1.0.101", optional = true, features = ["derive"] }
@@ -14,7 +14,7 @@ sr-primitives = { path = "../../../../core/sr-primitives", default-features = fa
 [features]
 default = ["std"]
 std = [
-	"client/std",
+	"sr-api/std",
 	"codec/std",
 	"rstd/std",
 	"serde",

substrate/srml/contracts/rpc/runtime-api/src/lib.rs

@@ -59,7 +59,7 @@ pub enum GetStorageError {
 	IsTombstone,
 }
 
-client::decl_runtime_apis! {
+sr_api::decl_runtime_apis! {
 	/// The API to interact with contracts without using executive.
 	pub trait ContractsApi<AccountId, Balance> where
 		AccountId: Codec,