Version 2.15.0-9.0.dev

Merge commit '3674c9122484c02ca39db7bca2e2875bde73f3b4' into 'dev'
diff --git a/DEPS b/DEPS
index c42dd21..1ffbaa5 100644
--- a/DEPS
+++ b/DEPS
@@ -45,7 +45,7 @@
   # hashes. It requires access to the dart-build-access group, which EngProd
   # has.
   "co19_rev": "3bbf92369652b6ba0b347516dabd1ed2193eb5c6",
-  "co19_2_rev": "d6e96f6d922b17fcf2e021e0f2b28835c861eb17",
+  "co19_2_rev": "7637bcb24abf21b5e2f8dd24d3fe619f777391f5",
 
   # The internal benchmarks to use. See go/dart-benchmarks-internal
   "benchmarks_internal_rev": "076df10d9b77af337f2d8029725787155eb1cd52",
diff --git a/tools/VERSION b/tools/VERSION
index e510752..d25666f 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 15
 PATCH 0
-PRERELEASE 8
+PRERELEASE 9
 PRERELEASE_PATCH 0
\ No newline at end of file