Adding utility method to test the version of the OS.

base/sys_info_ios.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/sys_info.h"
 
 #import <UIKit/UIKit.h>
 #include <mach/mach.h>
 #include <sys/sysctl.h>
 #include <sys/types.h>
@@ skipping 58 matching lines @@
 
 // static
 std::string SysInfo::CPUModelName() {
   char name[256];
   size_t len = arraysize(name);
   if (sysctlbyname("machdep.cpu.brand_string", &name, &len, NULL, 0) == 0)
     return name;
   return std::string();
 }
 
+// static
+bool SysInfo::IsRunningOnIOS5OrLater() {
+  return IsRunningOnOrLater(5, 0, 0);
+}
+
+// static
+bool SysInfo::IsRunningOnIOS6OrLater() {
+  return IsRunningOnOrLater(6, 0, 0);
+}
+
+// static
+bool SysInfo::IsRunningOnOrLater(int major, int minor, int bugFix) {
+  static int32 digits[3] = { 0, 0, 0 };
+  if (digits[0] == 0) {
+    OperatingSystemVersionNumbers(&digits[0], &digits[1], &digits[2]);
+  }
+  if (digits[0] < major)
+    return NO;
+  if (digits[0] > major)
+    return YES;
+  // digits[0] == major
+  if (digits[1] < minor)
+    return NO;
+  if (digits[1] > minor)
+    return YES;
+  // digits[1] == minor
+  if (digits[2] < bugFix)
+    return NO;
+  // digits[2] >= bugFix
+  return YES;
+}
+
 }  // namespace base