Migrate to OS_MAC and OS_APPLE in chrome/browser/ part 1

This migrates:

 defined(OS_MACOSX) -> defined(OS_APPLE)
 defined(OS_MACOSX) && !defined(OS_IOS) -> defined(OS_MAC)
 !defined(OS_MACOSX) || defined(OS_IOS) -> !defined(OS_MAC)

Bug: 1105907
Change-Id: I0590b7f22dd27637d7220ba4a09837421457638f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2321508
Reviewed-by: Alexei Svitkine <[email protected]>
Reviewed-by: Robert Sesek <[email protected]>
Commit-Queue: Robert Sesek <[email protected]>
Auto-Submit: Avi Drissman <[email protected]>
Cr-Commit-Position: refs/heads/master@{#792729}
diff --git a/chrome/browser/plugins/plugins_resource_service.cc b/chrome/browser/plugins/plugins_resource_service.cc
index 1e063a0c..f7354d4d 100644
--- a/chrome/browser/plugins/plugins_resource_service.cc
+++ b/chrome/browser/plugins/plugins_resource_service.cc
@@ -64,7 +64,7 @@
   filename = "plugins_chromeos.json";
 #elif defined(OS_LINUX)
   filename = "plugins_linux.json";
-#elif defined(OS_MACOSX)
+#elif defined(OS_MAC)
   filename = "plugins_mac.json";
 #else
 #error Unknown platform