MiraclePtr: revert rewriting BlobCache::mCache.

This is blocking the autoroller. I do not understand the failure.
This needs to be investigated separately. In the meantime, we
should revert this to unblock the autoroller.

Bug: dawn:2365
Change-Id: I4b2401deaa9315ac58f72e1679dd228ae42af405
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/171301
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Austin Eng <enga@chromium.org>
diff --git a/src/dawn/native/BlobCache.h b/src/dawn/native/BlobCache.h
index b749a34..57204a3 100644
--- a/src/dawn/native/BlobCache.h
+++ b/src/dawn/native/BlobCache.h
@@ -33,7 +33,7 @@
 #include "dawn/common/Platform.h"
 #include "dawn/native/Blob.h"
 #include "dawn/native/CacheResult.h"
-#include "partition_alloc/pointers/raw_ptr.h"
+#include "partition_alloc/pointers/raw_ptr_exclusion.h"
 
 namespace dawn::platform {
 class CachingInterface;
@@ -78,7 +78,8 @@
 
     // Protects thread safety of access to mCache.
     std::mutex mMutex;
-    raw_ptr<dawn::platform::CachingInterface> mCache;
+    // TODO(https://crbug.com/dawn/2365): Convert this member to `raw_ptr`.
+    RAW_PTR_EXCLUSION dawn::platform::CachingInterface* mCache;
 };
 
 }  // namespace dawn::native