Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

base/sys_info_mac.mm

Index: base/sys_info_mac.mm
diff --git a/base/sys_info_mac.mm b/base/sys_info_mac.mm
index aab1103d4c401d14efc6bf7eecb30c208b9a5d98..2e3d9fc32dceaee3af8c7f4f4a706a99c659caaf 100644
--- a/base/sys_info_mac.mm
+++ b/base/sys_info_mac.mm
@@ -51,7 +51,7 @@ void SysInfo::OperatingSystemVersionNumbers(int32_t* major_version,
     // cases in 10.9, rely on ::Gestalt(..). Since this code is only needed for
     // 10.9.0 and 10.9.1 and uses the recommended replacement thereafter,
     // suppress the warning for this fallback case.
-    DCHECK(base::mac::IsOS10_9());
+    DCHECK(!base::mac::IsAtLeastOS10_10());
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wdeprecated-declarations"
     Gestalt(gestaltSystemVersionMajor,