Mac: Avoid deprecated use of ::Gestalt() in base/sys_info_mac

base/sys_info_mac.mm

Index: base/sys_info_mac.mm
diff --git a/base/sys_info_mac.cc b/base/sys_info_mac.mm
similarity index 72%
rename from base/sys_info_mac.cc
rename to base/sys_info_mac.mm
index ff1ec5c1e69bb8b1cdce2eb08fc1db703c780402..08d7aaf3094266b95249083af40b3da33a9ea775 100644
--- a/base/sys_info_mac.cc
+++ b/base/sys_info_mac.mm
@@ -1,4 +1,4 @@
-// Copyright (c) 2012 The Chromium Authors. All rights reserved.
+// Copyright 2016 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.
 
@@ -6,6 +6,7 @@
 
 #include <ApplicationServices/ApplicationServices.h>
 #include <CoreServices/CoreServices.h>
+#import <Foundation/Foundation.h>
 #include <mach/mach_host.h>
 #include <mach/mach_init.h>
 #include <stddef.h>
@@ -14,7 +15,9 @@
 #include <sys/types.h>
 
 #include "base/logging.h"
+#include "base/mac/mac_util.h"
 #include "base/mac/scoped_mach_port.h"
+#import "base/mac/sdk_forward_declarations.h"
 #include "base/macros.h"
 #include "base/strings/stringprintf.h"
 
@@ -36,12 +39,24 @@ std::string SysInfo::OperatingSystemVersion() {
 void SysInfo::OperatingSystemVersionNumbers(int32_t* major_version,
                                             int32_t* minor_version,
                                             int32_t* bugfix_version) {
-  Gestalt(gestaltSystemVersionMajor,
-      reinterpret_cast<SInt32*>(major_version));
-  Gestalt(gestaltSystemVersionMinor,
-      reinterpret_cast<SInt32*>(minor_version));
-  Gestalt(gestaltSystemVersionBugFix,
-      reinterpret_cast<SInt32*>(bugfix_version));
+  NSProcessInfo* processInfo = [NSProcessInfo processInfo];
+  if ([processInfo respondsToSelector:@selector(operatingSystemVersion)]) {

[Nico, 2016/03/31 13:59:16]

Didn't someone say yesterday that this silently works on 10.9 too? Is the else
ever executed?

+    NSOperatingSystemVersion version = [processInfo operatingSystemVersion];
+    *major_version = version.majorVersion;
+    *minor_version = version.minorVersion;
+    *bugfix_version = version.patchVersion;
+  } else {
+    DCHECK(base::mac::IsOSMavericks());
+#pragma clang diagnostic push

[Nico, 2016/03/31 14:07:41]

Cool, can you add a comment here explaining why it's ok to call the old thing
here, that this will only run on 10.9 prior to 10.9.2, can be removed when we
stop supporting that, etc? I want every -Wdeprecated-declarations suppression to
have a very good reason for why it's there as a comment. (This here has a good
reason, it just needs a comment explaining it :-) )

[tapted, 2016/03/31 18:07:40]

Done. Added:

    // -[NSProcessInfo operatingSystemVersion] is documented available in 10.10.
    // It's also available via a private API since 10.9.2. For the remaining
    // cases in 10.9, rely on ::Gestalt(..). This can be removed once 10.9 is no
    // longer supported. Gestalt was deprecated in 10.8, so suppress the
    // deprecation warning.

+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+    Gestalt(gestaltSystemVersionMajor,
+            reinterpret_cast<SInt32*>(major_version));
+    Gestalt(gestaltSystemVersionMinor,
+            reinterpret_cast<SInt32*>(minor_version));
+    Gestalt(gestaltSystemVersionBugFix,
+            reinterpret_cast<SInt32*>(bugfix_version));
+#pragma clang diagnostic pop
+  }
 }
 
 // static