Replace OS X and Mac OS with macOS

atom/browser/ui/message_box_mac.mm

@@ -79,7 +79,7 @@ NSAlert* CreateNSAlert(NativeWindow* parent_window,
 
   for (size_t i = 0; i < buttons.size(); ++i) {
     NSString* title = base::SysUTF8ToNSString(buttons[i]);
-    // An empty title causes crash on OS X.
+    // An empty title causes crash on macOS.
     if (buttons[i].empty())
       title = @"(empty)";
     NSButton* button = [alert addButtonWithTitle:title];

atom/browser/ui/tray_icon.h

@@ -40,11 +40,11 @@ class TrayIcon {
   virtual void SetToolTip(const std::string& tool_tip) = 0;
 
   // Sets the title displayed aside of the status icon in the status bar. This
-  // only works on OS X.
+  // only works on macOS.
   virtual void SetTitle(const std::string& title);
 
   // Sets whether the status icon is highlighted when it is clicked. This only
-  // works on OS X.
+  // works on macOS.
   virtual void SetHighlightMode(bool highlight);
 
   // Displays a notification balloon with the specified contents.

atom/browser/ui/tray_icon_cocoa.mm

@@ -12,9 +12,9 @@
 
 namespace {
 
-// By default, OS X sets 4px to tray image as left and right padding margin.
+// By default, macOS sets 4px to tray image as left and right padding margin.
 const CGFloat kHorizontalMargin = 4;
-// OS X tends to make the title 2px lower.
+// macOS tends to make the title 2px lower.
 const CGFloat kVerticalTitleMargin = 2;
 
 }  //  namespace