Mac Overlays: Wire up overlays on Mac

ui/gl/gl_image_io_surface.h

Index: ui/gl/gl_image_io_surface.h
diff --git a/ui/gl/gl_image_io_surface.h b/ui/gl/gl_image_io_surface.h
index b3f695afab7154f028c1f45f359775b51188bd81..28a1e19b80e96579ebce5a58bc20bd3b082996ed 100644
--- a/ui/gl/gl_image_io_surface.h
+++ b/ui/gl/gl_image_io_surface.h
@@ -12,6 +12,12 @@
 #include "ui/gfx/gpu_memory_buffer.h"
 #include "ui/gl/gl_image.h"
 
+#if defined(__OBJC__)
+@class CALayer;
+#else
+typedef void* CALayer;
+#endif
+
 namespace gfx {
 
 class GL_EXPORT GLImageIOSurface : public GLImage {
@@ -39,6 +45,9 @@ class GL_EXPORT GLImageIOSurface : public GLImage {
                             const Rect& bounds_rect,
                             const RectF& crop_rect) override;
 
+  static void SetLayerForWidget(gfx::AcceleratedWidget widget,
+                                CALayer* layer);
+
  protected:
   ~GLImageIOSurface() override;