Delete IsAtLeastOS10_9() and IsAtMostOS10_9()

base/sys_info_mac.mm

 // 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.
 
 #include "base/sys_info.h"
 
 #include <ApplicationServices/ApplicationServices.h>
 #include <CoreServices/CoreServices.h>
 #import <Foundation/Foundation.h>
 #include <mach/mach_host.h>
@@ skipping 33 matching lines @@
     NSOperatingSystemVersion version = [processInfo operatingSystemVersion];
     *major_version = version.majorVersion;
     *minor_version = version.minorVersion;
     *bugfix_version = version.patchVersion;
   } else {
     // -[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(..). Since this code is only needed for
     // 10.9.0 and 10.9.1 and uses the recommended replacement thereafter,
     // suppress the warning for this fallback case.
-    DCHECK(base::mac::IsOS10_9());

[Nico, 2016/08/29 19:44:23]

Hm, the lhs seems better to me. When we dropped old macOS versions in the past,
we grepped for (say) "10.8" and that let us find a bunch of code to delete. This
is now harder. Is there any rush to remove Is10_9?

[Sidney San Martín, 2016/08/30 15:27:04]

FWIW, grepping doesn't get any harder. When we drop 10.9, we'd search for:

- IsAtLeastOS10_10(): now guaranteed to be true with or without `!`, time to
delete some code.
- IsOS10_10() -> !IsAtLeastOS10_11()
- IsAtMost10_10() -> !IsAtLeastOS10_11()

…and then we could delete the *10_10() functions.

On the other hand, if it's more of a semantic meaning/readability thing —
IsOS10_9() doesn't actually mean the same thing as !IsOS10_10(), even though it
does in practice — then how do you feel about reinstating IsOS10_9() and
reverting the more-confusing changes?

[Sidney San Martín, 2016/08/30 15:27:55]

See latest patch set.

+    DCHECK(!base::mac::IsAtLeastOS10_10());
 #pragma clang diagnostic push
 #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
   }
@@ skipping 45 matching lines @@
 
 std::string SysInfo::HardwareModelName() {
   char model[256];
   size_t len = sizeof(model);
   if (sysctlbyname("hw.model", model, &len, NULL, 0) == 0)
     return std::string(model, 0, len);
   return std::string();
 }
 
 }  // namespace base