Updating trunk VERSION from 2538.0 to 2539.0

Cr-Commit-Position: refs/heads/master@{#354665}
diff --git a/chrome/VERSION b/chrome/VERSION
index d50d23de..0809f6c7 100644
--- a/chrome/VERSION
+++ b/chrome/VERSION
@@ -1,4 +1,4 @@
 MAJOR=48
 MINOR=0
-BUILD=2538
+BUILD=2539
 PATCH=0