Add plumbing for the GrThreadSafeUniquelyKeyedProxyViewCache

This CL is also imperfect and incomplete but, although currently unused, it sketches in how the threadSafeProxyCache will be plumbed through the GrContexts and GrResourceCache.

Bug: 1108408
Change-Id: Idb012b6efd49291de69bd88e4b4c531458a3e553
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/317360
Reviewed-by: Adlai Holler <adlai@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
diff --git a/src/gpu/GrContextPriv.h b/src/gpu/GrContextPriv.h
index e28b8ad..3ac7be2 100644
--- a/src/gpu/GrContextPriv.h
+++ b/src/gpu/GrContextPriv.h
@@ -58,6 +58,10 @@
     GrStrikeCache* getGrStrikeCache() { return fContext->fStrikeCache.get(); }
     GrTextBlobCache* getTextBlobCache() { return fContext->getTextBlobCache(); }
 
+    GrThreadSafeUniquelyKeyedProxyViewCache* threadSafeViewCache() {
+        return fContext->threadSafeViewCache();
+    }
+
     /**
      * Registers an object for flush-related callbacks. (See GrOnFlushCallbackObject.)
      *