Dynamic Benchmarking DB Whitelist (#6815)

* Add `get_whitelist` api

* add whitelisted caller

* Whitelist caller

* remove caller 0

* initial piping of origin (not actual value yet)

* remove attempt to pass origin around

* Add whitelist for `DidUpdate` storage on `pallet_timestamp`

* fix traits

* only add to whitelist if !contains

* PassBy not implemented error

* Whitelist read/writes explicitly per key

* update docs

* reduce trait constraint

* copy pasta

* Apply suggestions from code review

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

* rename functions @apopiak

* missed some renaming

* enable doc tests

* Update docs

Co-authored-by: Guillaume Thiolliere <gui.thiolliere@gmail.com>
Co-authored-by: Alexander Popiak <alexander.popiak@parity.io>

substrate/primitives/storage/src/lib.rs

@@ -25,6 +25,7 @@ use sp_debug_derive::RuntimeDebug;
 
 use sp_std::{vec::Vec, ops::{Deref, DerefMut}};
 use ref_cast::RefCast;
+use codec::{Encode, Decode};
 
 /// Storage key.
 #[derive(PartialEq, Eq, RuntimeDebug)]
@@ -34,6 +35,26 @@ pub struct StorageKey(
 	pub Vec<u8>,
 );
 
+/// Storage key with read/write tracking information.
+#[derive(PartialEq, Eq, RuntimeDebug, Clone, Encode, Decode)]
+#[cfg_attr(feature = "std", derive(Hash, PartialOrd, Ord))]
+pub struct TrackedStorageKey {
+	pub key: Vec<u8>,
+	pub has_been_read: bool,
+	pub has_been_written: bool,
+}
+
+// Easily convert a key to a `TrackedStorageKey` that has been read and written to.
+impl From<Vec<u8>> for TrackedStorageKey {
+	fn from(key: Vec<u8>) -> Self {
+		Self {
+			key: key,
+			has_been_read: true,
+			has_been_written: true,
+		}
+	}
+}
+
 /// Storage key of a child trie, it contains the prefix to the key.
 #[derive(PartialEq, Eq, RuntimeDebug)]
 #[cfg_attr(feature = "std", derive(Serialize, Deserialize, Hash, PartialOrd, Ord, Clone))]