Remove SkPaint::getHash

This was a particularly bad hash (A == B didn't imply
hash(A) == hash(B)). It was also entirely unused.

Change-Id: Id923bf1035effce04e12b1cc01d1c6aa4d11fdb6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/419336
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>
diff --git a/RELEASE_NOTES.txt b/RELEASE_NOTES.txt
index d938667..e671525 100644
--- a/RELEASE_NOTES.txt
+++ b/RELEASE_NOTES.txt
@@ -6,7 +6,8 @@
 
 Milestone 93
 ------------
-  *
+  * Removed SkPaint::getHash
+    https://review.skia.org/419336
 
 * * *