Improve and unify Mac OS X run-time version checks

chrome/browser/ui/cocoa/objc_zombie.mm

 // Copyright (c) 2011 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.
 
 #import "chrome/browser/ui/cocoa/objc_zombie.h"
 
 #include <dlfcn.h>
 #include <mach-o/dyld.h>
 #include <mach-o/nlist.h>
 
 #import <objc/objc-class.h>
 
 #include "base/logging.h"
+#include "base/mac/mac_util.h"
 #include "base/metrics/histogram.h"
 #include "base/synchronization/lock.h"
-#include "base/sys_info.h"
 #import "chrome/app/breakpad_mac.h"
 #import "chrome/browser/ui/cocoa/objc_method_swizzle.h"
 
 // Deallocated objects are re-classed as |CrZombie|.  No superclass
 // because then the class would have to override many/most of the
 // inherited methods (|NSObject| is like a category magnet!).
 @interface CrZombie {
   Class isa;
 }
 @end
@@ skipping 245 matching lines @@
   UMA_HISTOGRAM_ENUMERATION("OSX.ZombieInitFailure", failure, FAILED_MAX);
 }
 
 // Initialize our globals, returning YES on success.
 BOOL ZombieInit() {
   static BOOL initialized = NO;
   if (initialized)
     return YES;
 
   // Whitelist releases that are compatible with objc zombies.
-  int32 major_version = 0, minor_version = 0, bugfix_version = 0;
-  base::SysInfo::OperatingSystemVersionNumbers(
-      &major_version, &minor_version, &bugfix_version);
-
-  if (major_version < 10 || (major_version == 10 && minor_version < 5)) {
-    return NO;
-  } else if (major_version == 10 && minor_version == 5) {
+  if (base::mac::IsOSLeopard()) {
     g_objectDestruct = LookupObjectDestruct_10_5();
     if (!g_objectDestruct) {
       RecordZombieFailure(FAILED_10_5);
       return NO;
     }
-  } else if (major_version == 10 && minor_version == 6) {
+  } else if (base::mac::IsOSSnowLeopard()) {
     g_objectDestruct = LookupObjectDestruct_10_6();
     if (!g_objectDestruct) {
       RecordZombieFailure(FAILED_10_6);
       return NO;
     }
-  } else {
+  } else if (base::mac::IsOSLionOrLater()) {
     // Assume the future looks like the present.
     g_objectDestruct = LookupObjectDestruct_10_6();
 
     // Put all future failures into the MAX bin.  New OS releases come
     // out infrequently enough that this should always correspond to
     // "Next release", and once the next release happens that bin will
     // get an official name.
     if (!g_objectDestruct) {
       RecordZombieFailure(FAILED_MAX);
       return NO;
     }
+  } else {
+    return NO;
   }
 
   Class rootClass = [NSObject class];
   g_originalDeallocIMP =
       class_getMethodImplementation(rootClass, @selector(dealloc));
   // objc_getClass() so CrZombie doesn't need +class.
   g_zombieClass = objc_getClass("CrZombie");
   g_fatZombieClass = objc_getClass("CrFatZombie");
   g_fatZombieSize = class_getInstanceSize(g_fatZombieClass);
 
@@ skipping 175 matching lines @@
   if (oldZombies) {
     for (size_t i = 0; i < oldCount; ++i) {
       if (oldZombies[i].object)
         object_dispose(oldZombies[i].object);
     }
     free(oldZombies);
   }
 }
 
 }  // namespace ObjcEvilDoers