Introduce OS_MAC

In the spirit of macOS Big Sur, which is labeled as macOS 11.0,
introduce OS_MAC and OS_APPLE. OS_MACOSX implicitly included OS_IOS,
which was confusing, so OS_APPLE is the new replacement for "macOS +
iOS" and OS_MAC is the new replacement for "just macOS, not iOS".

Bug: 1105907
Change-Id: I0f24ff5a74f07eaf2fe7b7fa17bdef7e82a514fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2299189
Reviewed-by: Nico Weber <[email protected]>
Reviewed-by: Daniel Cheng <[email protected]>
Reviewed-by: Leonard Grey <[email protected]>
Reviewed-by: Elly Fong-Jones <[email protected]>
Auto-Submit: Avi Drissman <[email protected]>
Commit-Queue: Avi Drissman <[email protected]>
Cr-Commit-Position: refs/heads/master@{#791353}
diff --git a/PRESUBMIT_test.py b/PRESUBMIT_test.py
index edba20f..8286775 100755
--- a/PRESUBMIT_test.py
+++ b/PRESUBMIT_test.py
@@ -274,8 +274,7 @@
   def testInvalidOSMacroNames(self):
     lines = ['#if defined(OS_WINDOWS)',
              ' #elif defined(OS_WINDOW)',
-             ' # if defined(OS_MACOSX) || defined(OS_CHROME)',
-             '# else  // defined(OS_MAC)',
+             ' # if defined(OS_MAC) || defined(OS_CHROME)',
              '#endif  // defined(OS_MACOS)']
     errors = PRESUBMIT._CheckForInvalidOSMacrosInFile(
         MockInputApi(), MockFile('some/path/foo_platform.cc', lines))