[MacViews] Use NSTitledWindowMask for window modal dialogs.

ui/views/widget/native_widget_mac.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.
 
 #include "ui/views/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
@@ skipping 20 matching lines @@
 }
 
 + (void)closeWindowWithAnimation:(NSWindow*)window;
 
 @end
 
 namespace views {
 namespace {
 
 NSInteger StyleMaskForParams(const Widget::InitParams& params) {
+  // If the widget is modal, it will be displayed as a sheet. This only works

[tapted, 2015/08/19 09:02:14]

nit: widget -> Widget
(and perhaps "only works" -> "works best")

[jackhou1, 2015/08/20 00:01:36]

Done.

+  // if it has NSTitledWindowMask.

[tapted, 2015/08/19 09:02:14]

nit: perhaps worth adding "(e.g. with NSBorderlessWindowMask. the parent window
still accepts input)."

[jackhou1, 2015/08/20 00:01:36]

Done.

+  if (params.delegate->GetModalType() == ui::MODAL_TYPE_WINDOW)

[tapted, 2015/08/19 09:02:14]

params.delegate && ... 

(params.delegate can be null)

[jackhou1, 2015/08/20 00:01:36]

Done.

+    return NSTitledWindowMask;
+
   // TODO(tapted): Determine better masks when there are use cases for it.
   if (params.remove_standard_frame)
     return NSBorderlessWindowMask;
 
   if (params.type == Widget::InitParams::TYPE_WINDOW) {
     return NSTitledWindowMask | NSClosableWindowMask |
            NSMiniaturizableWindowMask | NSResizableWindowMask |
            NSTexturedBackgroundWindowMask;
   }
   return NSBorderlessWindowMask;
@@ skipping 649 matching lines @@
   [[ViewsNSWindowCloseAnimator alloc] initWithWindow:window];
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [window_ close];
   [animation_ setDelegate:nil];
   [self release];
 }
 
 @end