Send TextBlobCache purge messages only to owning cache.

Bug: 703297
Change-Id: I95cdaa5bdebadd5ce88ae3ee468c59baa08353c6
Reviewed-on: https://skia-review.googlesource.com/85046
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
diff --git a/include/core/SkTextBlob.h b/include/core/SkTextBlob.h
index 228747a..b27ec87 100644
--- a/include/core/SkTextBlob.h
+++ b/include/core/SkTextBlob.h
@@ -98,17 +98,17 @@
 
     // Call when this blob is part of the key to a cache entry. This allows the cache
     // to know automatically those entries can be purged when this SkTextBlob is deleted.
-    void notifyAddedToCache() const {
-        fAddedToCache.store(true);
+    void notifyAddedToCache(uint32_t cacheID) const {
+        fCacheID.store(cacheID);
     }
 
     friend class GrTextBlobCache;
     friend class SkTextBlobBuilder;
     friend class SkTextBlobRunIterator;
 
-    const SkRect           fBounds;
-    const uint32_t         fUniqueID;
-    mutable SkAtomic<bool> fAddedToCache;
+    const SkRect               fBounds;
+    const uint32_t             fUniqueID;
+    mutable SkAtomic<uint32_t> fCacheID;
 
     SkDEBUGCODE(size_t fStorageSize;)