MacViews: Exploring removal of window-modal sheets.

ui/views/widget/native_widget_mac.mm

Index: ui/views/widget/native_widget_mac.mm
diff --git a/ui/views/widget/native_widget_mac.mm b/ui/views/widget/native_widget_mac.mm
index e81bba45df906f90e4c03351acf778f22318c7a0..9c935c1217c29eb898f544ccf1d0a8cac1e5ec67 100644
--- a/ui/views/widget/native_widget_mac.mm
+++ b/ui/views/widget/native_widget_mac.mm
@@ -45,11 +45,15 @@
 namespace views {
 namespace {
 
+bool SheetsEnabled() {
+  return false;
+}
+
 NSInteger StyleMaskForParams(const Widget::InitParams& params) {
   // If the Widget is modal, it will be displayed as a sheet. This works best if
   // it has NSTitledWindowMask. For example, with NSBorderlessWindowMask, the
   // parent window still accepts input.
-  if (params.delegate &&
+  if (SheetsEnabled() && params.delegate &&
       params.delegate->GetModalType() == ui::MODAL_TYPE_WINDOW)
     return NSTitledWindowMask;
 
@@ -96,7 +100,7 @@ BridgedNativeWidget* NativeWidgetMac::GetBridgeForNativeWindow(
 }
 
 bool NativeWidgetMac::IsWindowModalSheet() const {
-  return bridge_ && bridge_->parent() &&
+  return SheetsEnabled() && bridge_ && bridge_->parent() &&
          GetWidget()->widget_delegate()->GetModalType() ==
              ui::MODAL_TYPE_WINDOW;
 }