dawn_native: Do attachment state validation at encoding time.

The overarching goal with this CL is to do validation at encoding time
which will help produce SyncScopeResourceUsage in the frontend for
dispatch() calls so that they can be reused by the backends.

Bug: dawn:635
Change-Id: Ifb8b7883abe18089dc3d632baebbcc79b3f324f7
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/38843
Commit-Queue: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Stephen White <senorblanco@chromium.org>

src/dawn_native/RenderBundle.cpp

@@ -23,11 +23,11 @@ namespace dawn_native {
 
     RenderBundleBase::RenderBundleBase(RenderBundleEncoder* encoder,
                                        const RenderBundleDescriptor* descriptor,
-                                       AttachmentState* attachmentState,
+                                       Ref<AttachmentState> attachmentState,
                                        PassResourceUsage resourceUsage)
         : ObjectBase(encoder->GetDevice()),
           mCommands(encoder->AcquireCommands()),
-          mAttachmentState(attachmentState),
+          mAttachmentState(std::move(attachmentState)),
           mResourceUsage(std::move(resourceUsage)) {
     }