Adding utility method to test the version of the OS.

base/ios/ios_util.mm

+// Copyright 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/ios/ios_util.h"
+
+#include "base/sys_info.h"
+
+namespace {
+// Return a 3 elements array containing the major, minor and bug fix version of
+// the OS.
+const int32* OSVersionAsArray() {
+  int32* digits = new int32[3];
+  base::SysInfo::OperatingSystemVersionNumbers(
+      &digits[0], &digits[1], &digits[2]);
+  return digits;
+}
+}  // namespace
+
+namespace base {
+namespace ios {
+
+bool IsRunningOnIOS5OrLater() {
+  return IsRunningOnOrLater(5, 0, 0);
+}
+
+bool IsRunningOnIOS6OrLater() {
+  return IsRunningOnOrLater(6, 0, 0);
+}
+
+bool IsRunningOnOrLater(int32 major, int32 minor, int32 bug_fix) {
+  static const int32* current_version = OSVersionAsArray();
+  int32 version[] = { major, minor, bug_fix };
+  for (size_t i = 0; i < arraysize(version); i++) {
+    if (current_version[i] != version[i])
+      return current_version[i] > version[i];
+  }
+  return true;
+}
+
+}  // namespace ios
+}  // namespace base