Adding utility method to test the version of the OS.

base/sys_info_ios.mm

Index: base/sys_info_ios.mm
diff --git a/base/sys_info_ios.mm b/base/sys_info_ios.mm
index 8b1ffd4521192f0f9db7e9c2b3b6621a4e6d1838..8b25ef5c631eb6d0dd4d4ff00548aacf7d216c00 100644
--- a/base/sys_info_ios.mm
+++ b/base/sys_info_ios.mm
@@ -76,4 +76,36 @@ std::string SysInfo::CPUModelName() {
   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