Improve and unify Mac OS X run-time version checks

content/browser/renderer_host/backing_store_mac.mm

Index: content/browser/renderer_host/backing_store_mac.mm
===================================================================
--- content/browser/renderer_host/backing_store_mac.mm	(revision 88826)
+++ content/browser/renderer_host/backing_store_mac.mm	(working copy)
@@ -9,7 +9,6 @@
 #include "base/logging.h"
 #include "base/mac/mac_util.h"
 #include "base/mac/scoped_cftyperef.h"
-#include "base/sys_info.h"
 #include "content/browser/renderer_host/render_process_host.h"
 #include "content/browser/renderer_host/render_widget_host.h"
 #include "content/browser/renderer_host/render_widget_host_view.h"
@@ -31,10 +30,7 @@
 // Returns whether this version of OS X has broken CGLayers, see
 // http://crbug.com/45553 , comments 5 and 6.
 bool NeedsLayerWorkaround() {
-  int32 os_major, os_minor, os_bugfix;
-  base::SysInfo::OperatingSystemVersionNumbers(
-      &os_major, &os_minor, &os_bugfix);
-  return os_major == 10 && os_minor == 5;
+  return base::mac::IsOSLeopard();
 }
 
 }  // namespace