Remove StorageList (#2725)

* Remove `StorageList`

`StorageList` is not used anymore by `decl_storage!` and thus, it can be
removed.

* Fixes tests

substrate/srml/support/src/storage/mod.rs

@@ -196,74 +196,6 @@ impl<T: Codec, U> StorageValue<T> for U where U: hashed::generator::StorageValue
 	}
 }
 
-/// A strongly-typed list in storage.
-pub trait StorageList<T: Codec> {
-	/// Get the prefix key in storage.
-	fn prefix() -> &'static [u8];
-
-	/// Get the key used to store the length field.
-	fn len_key() -> Vec<u8>;
-
-	/// Get the storage key used to fetch a value at a given index.
-	fn key_for(index: u32) -> Vec<u8>;
-
-	/// Read out all the items.
-	fn items() -> Vec<T>;
-
-	/// Set the current set of items.
-	fn set_items(items: &[T]);
-
-	/// Set the item at the given index.
-	fn set_item<Arg: Borrow<T>>(index: u32, val: Arg);
-
-	/// Load the value at given index. Returns `None` if the index is out-of-bounds.
-	fn get(index: u32) -> Option<T>;
-
-	/// Load the length of the list
-	fn len() -> u32;
-
-	/// Clear the list.
-	fn clear();
-}
-
-impl<T: Codec, U> StorageList<T> for U where U: hashed::generator::StorageList<T> {
-	fn prefix() -> &'static [u8] {
-		<U as hashed::generator::StorageList<T>>::prefix()
-	}
-
-	fn len_key() -> Vec<u8> {
-		<U as hashed::generator::StorageList<T>>::len_key()
-	}
-
-	fn key_for(index: u32) -> Vec<u8> {
-		<U as hashed::generator::StorageList<T>>::key_for(index)
-	}
-
-	fn items() -> Vec<T> {
-		U::items(&RuntimeStorage)
-	}
-
-	fn set_items(items: &[T]) {
-		U::set_items(items, &mut RuntimeStorage)
-	}
-
-	fn set_item<Arg: Borrow<T>>(index: u32, val: Arg) {
-		U::set_item(index, val.borrow(), &mut RuntimeStorage)
-	}
-
-	fn get(index: u32) -> Option<T> {
-		U::get(index, &RuntimeStorage)
-	}
-
-	fn len() -> u32 {
-		U::len(&RuntimeStorage)
-	}
-
-	fn clear() {
-		U::clear(&mut RuntimeStorage)
-	}
-}
-
 /// A strongly-typed map in storage.
 pub trait StorageMap<K: Codec, V: Codec> {
 	/// The type that get/take return.