dawn_wire: Add an API to reclaim reserved devices and textures

Dawn Wire has a way to reserve an ID and generation on the client side,
but if these reservations are never injected on the server, then
it will be impossible to reclaim the in-use ObjectIDs.

Bug: dawn:565
Change-Id: I751fce237c881e8cbdeaba18ad0ec1e124bd7ac2
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/38281
Commit-Queue: Austin Eng <enga@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>

src/dawn_wire/client/Client.cpp

@@ -118,6 +118,14 @@ namespace dawn_wire { namespace client {
         return result;
     }
 
+    void Client::ReclaimTextureReservation(const ReservedTexture& reservation) {
+        TextureAllocator().Free(FromAPI(reservation.texture));
+    }
+
+    void Client::ReclaimDeviceReservation(const ReservedDevice& reservation) {
+        DeviceAllocator().Free(FromAPI(reservation.device));
+    }
+
     void Client::Disconnect() {
         mDisconnected = true;
         mSerializer = ChunkedCommandSerializer(NoopCommandSerializer::GetInstance());