Update SKP version

Automatic commit by the RecreateSKPs bot.

TBR=
NO_MERGE_BUILDS

Review URL: https://codereview.chromium.org/1401013002
diff --git a/SKP_VERSION b/SKP_VERSION
index 88bc40f..7c2b018 100644
--- a/SKP_VERSION
+++ b/SKP_VERSION
@@ -1 +1 @@
-513
\ No newline at end of file
+521
\ No newline at end of file