Bug 1903508 - Part 4: Implement nsLookAndFeel::GetKeyboardLayoutImpl() for the MAC platform. r=emilio

Differential Revision: https://phabricator.services.mozilla.com/D215073

widget/cocoa/nsLookAndFeel.h

@@ -31,6 +31,8 @@ class nsLookAndFeel final : public nsXPLookAndFeel {
     RecordAccessibilityTelemetry();
   }
 
+  nsresult GetKeyboardLayoutImpl(nsACString& aLayout) override;
+
   // Having a separate, static method allows us to rely on the same
   // chunk of telemetry logging code at initialization and when we
   // recieve an event that changes the value of our telemetry probe.

widget/cocoa/nsLookAndFeel.mm

@@ -18,6 +18,7 @@
 #include "mozilla/StaticPrefs_widget.h"
 #include "mozilla/Telemetry.h"
 #include "mozilla/widget/WidgetMessageUtils.h"
+#include "mozilla/MacStringHelpers.h"
 
 #import <Cocoa/Cocoa.h>
 #import <AppKit/NSColor.h>
@@ -581,6 +582,19 @@ void nsLookAndFeel::RecordAccessibilityTelemetry() {
   }
 }
 
+nsresult nsLookAndFeel::GetKeyboardLayoutImpl(nsACString& aLayout) {
+  TISInputSourceRef source = TISCopyCurrentKeyboardInputSource();
+  nsAutoString layout;
+
+  CFStringRef layoutName = static_cast<CFStringRef>(
+      TISGetInputSourceProperty(source, kTISPropertyLocalizedName));
+  CopyNSStringToXPCOMString((const NSString*)layoutName, layout);
+  aLayout.Assign(NS_ConvertUTF16toUTF8(layout));
+
+  CFRelease(source);
+  return NS_OK;
+}
+
 @implementation MOZLookAndFeelDynamicChangeObserver
 
 + (void)startObserving {