MacViews: Hide windows before closing.

ui/views/cocoa/bridged_native_widget.mm

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import "ui/views/cocoa/bridged_native_widget.h"
 
 #import <objc/runtime.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 345 matching lines @@
 BridgedNativeWidget::~BridgedNativeWidget() {
   // The delegate should be cleared already. Note this enforces the precondition
   // that -[NSWindow close] is invoked on the hosted window before the
   // destructor is called.
   DCHECK(![window_ delegate]);
 
   RemoveOrDestroyChildren();
   DCHECK(child_windows_.empty());
   SetFocusManager(nullptr);
   SetRootView(nullptr);
+
+  DCHECK(![window_ isVisible]);
   DestroyCompositor();
 }
 
 void BridgedNativeWidget::Init(base::scoped_nsobject<NSWindow> window,
                                const Widget::InitParams& params) {
   widget_type_ = params.type;
 
   DCHECK(!window_);
   window_.swap(window);
   [window_ setDelegate:window_delegate_];
@@ skipping 298 matching lines @@
 void* BridgedNativeWidget::GetNativeWindowProperty(const char* name) const {
   NSString* key = [NSString stringWithUTF8String:name];
   return [[GetWindowProperties() objectForKey:key] pointerValue];
 }
 
 void BridgedNativeWidget::SetCursor(NSCursor* cursor) {
   [window_delegate_ setCursor:cursor];
 }
 
 void BridgedNativeWidget::OnWindowWillClose() {
+  // Hide the window before closing. This ensures that destroying the compositor
+  // during the close does not cause a flash, which would be the case if the
+  // window was still visible.
+  SetVisibilityState(HIDE_WINDOW);
+
   native_widget_mac_->GetWidget()->OnNativeWidgetDestroying();
 
   // Ensure BridgedNativeWidget does not have capture, otherwise
   // OnMouseCaptureLost() may reference a deleted |native_widget_mac_| when
   // called via ~CocoaMouseCapture() upon the destruction of |mouse_capture_|.
   // See crbug.com/622201. Also we do this before setting the delegate to nil,
   // because this may lead to callbacks to bridge which rely on a valid
   // delegate.
   ReleaseCapture();
 
@@ skipping 684 matching lines @@
   [bridged_view_ setMouseDownCanMoveWindow:draggable];
   // AppKit will not update its cache of mouseDownCanMoveWindow unless something
   // changes. Previously we tried adding an NSView and removing it, but for some
   // reason it required reposting the mouse-down event, and didn't always work.
   // Calling the below seems to be an effective solution.
   [window_ setMovableByWindowBackground:NO];
   [window_ setMovableByWindowBackground:YES];
 }
 
 }  // namespace views