Remove NSWindowHostsLayersInWindowServer workaround.

content/app/mac/mac_init.mm

Index: content/app/mac/mac_init.mm
diff --git a/content/app/mac/mac_init.mm b/content/app/mac/mac_init.mm
index bd11bf49a317d1950d1c25f4793fd0369a6857c0..5bcd537999d31170024a4fd087bd92a9f4ca465a 100644
--- a/content/app/mac/mac_init.mm
+++ b/content/app/mac/mac_init.mm
@@ -19,13 +19,6 @@ void InitializeMac() {
       // application:openFile:], because they are handled directly. @"NO" looks
       // like a mistake, but the value really is supposed to be a string.
       @"NSTreatUnknownArgumentsAsOpen": @"NO",
-
-      // CoreAnimation has poor performance and CoreAnimation and
-      // non-CoreAnimation exhibit window flickering when layers are not hosted
-      // in the window server, which is the default when not not using the
-      // 10.9 SDK.
-      // TODO: Remove this when we build with the 10.9 SDK.
-      @"NSWindowHostsLayersInWindowServer": @YES
   }];
 }