Add deprecation TODO for BrowserWindow.showDefinitionForSelection

atom/browser/native_window_mac.mm

@@ -934,6 +934,8 @@ void NativeWindowMac::SetOverlayIcon(const gfx::Image& overlay,
 }
 
 void NativeWindowMac::ShowDefinitionForSelection() {
+  // TODO(kevinsawicki): Deprecate and remove this method in 2.0 in favor of
+  // calling it directly on webContents.
   if (!web_contents())
     return;
   auto rwhv = web_contents()->GetRenderWidgetHostView();