Roll Flutter from 9526c84b2e48 to 52d17b667250 (2 revisions) (#1523)

diff --git a/.ci/flutter_master.version b/.ci/flutter_master.version
index 5c830b3..6c29c6d 100644
--- a/.ci/flutter_master.version
+++ b/.ci/flutter_master.version
@@ -1 +1 @@
-9526c84b2e48331260f119687498f32424635730
+52d17b667250c6f126f0a03cec04b6a8c72dee04