Nuke Builders Part 2: remove all builder code from wire

This removes blocks of code that were obviously builder-specific but
also removes the ObjectStorage::valid member that was used to implement
the maybe monad on the wire server side. This is no longer needed since
dawn_native handles the maybe monad internally now.

BUG=dawn:125

Change-Id: I8c30daae9fc70853bc1996d85a860b4877c5976c
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/6161
Reviewed-by: Austin Eng <enga@chromium.org>
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Commit-Queue: Corentin Wallez <cwallez@chromium.org>

src/dawn_wire/client/ObjectBase.h

@@ -21,24 +21,6 @@ namespace dawn_wire { namespace client {
 
     class Device;
 
-    struct BuilderCallbackData {
-        bool Call(DawnBuilderErrorStatus status, const char* message) {
-            if (canCall && callback != nullptr) {
-                canCall = true;
-                callback(status, message, userdata1, userdata2);
-                return true;
-            }
-
-            return false;
-        }
-
-        // For help with development, prints all builder errors by default.
-        DawnBuilderErrorCallback callback = nullptr;
-        DawnCallbackUserdata userdata1 = 0;
-        DawnCallbackUserdata userdata2 = 0;
-        bool canCall = true;
-    };
-
     // All non-Device objects of the client side have:
     //  - A pointer to the device to get where to serialize commands
     //  - The external reference count
@@ -51,8 +33,6 @@ namespace dawn_wire { namespace client {
         Device* device;
         uint32_t refcount;
         uint32_t id;
-
-        BuilderCallbackData builderCallback;
     };
 
 }}  // namespace dawn_wire::client