MacViews: Suppress visibility changes during an asynchronous close.

ui/views/cocoa/bridged_native_widget.h

Index: ui/views/cocoa/bridged_native_widget.h
diff --git a/ui/views/cocoa/bridged_native_widget.h b/ui/views/cocoa/bridged_native_widget.h
index ba4c5847c735b1b578388f5291367c34e34896fc..eb723f1e76e79f9751491d713957c83722fa2ac9 100644
--- a/ui/views/cocoa/bridged_native_widget.h
+++ b/ui/views/cocoa/bridged_native_widget.h
@@ -95,6 +95,8 @@ class VIEWS_EXPORT BridgedNativeWidget
   // descendant windows where necessary.
   void SetVisibilityState(WindowVisibilityState new_state);
 
+  void CloseAsynchronously();
+
   // Acquiring mouse capture first steals capture from any existing
   // CocoaMouseCaptureDelegate, then captures all mouse events until released.
   void AcquireCapture();
@@ -227,6 +229,11 @@ class VIEWS_EXPORT BridgedNativeWidget
   // frame is ready, or a timeout occurs.
   void MaybeWaitForFrame(const gfx::Size& size_in_dip);
 
+  // Return true if the Widget delegate's modal type is window-modal. These
+  // display as a native window "sheet", and have a different lifetime to
+  // regular windows.
+  bool IsWindowModalSheet() const;
+
   // Show the window using -[NSApp beginSheet:..], modal for the parent window.
   void ShowAsModalSheet();
 
@@ -311,6 +318,11 @@ class VIEWS_EXPORT BridgedNativeWidget
   // shadow needs to be invalidated when a frame is received for the new shape.
   bool invalidate_shadow_on_frame_swap_ = false;
 
+  // Set when an asynchronous close is pending. Visibility changes should be
+  // suppressed in this case. For a synchronous close (e.g. via -[NSWindow
+  // close]), the NSWindowDelegate is just set to nil.
+  bool close_pending_ = false;
+
   AssociatedViews associated_views_;
 
   DISALLOW_COPY_AND_ASSIGN(BridgedNativeWidget);