Use a uniform opaque type to represent web contents modal dialogs

chrome/browser/ui/native_web_contents_modal_dialog.h

Index: chrome/browser/ui/native_web_contents_modal_dialog.h
diff --git a/chrome/browser/ui/native_web_contents_modal_dialog.h b/chrome/browser/ui/native_web_contents_modal_dialog.h
new file mode 100644
index 0000000000000000000000000000000000000000..4c5865bb85c4eff367712a7425ae3b4bb9b66802
--- /dev/null
+++ b/chrome/browser/ui/native_web_contents_modal_dialog.h
@@ -0,0 +1,19 @@
+// Copyright (c) 2013 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.
+
+#ifndef CHROME_BROWSER_UI_NATIVE_WEB_CONTENTS_MODAL_DIALOG_H_
+#define CHROME_BROWSER_UI_NATIVE_WEB_CONTENTS_MODAL_DIALOG_H_
+
+#include "ui/gfx/native_widget_types.h"
+
+#if defined(OS_MACOSX)
+// Use a specific type since none of the gfx::Native* types are suitable for
+// representing the web contents modal dialog under Cocoa.
+@protocol ConstrainedWindowSheet;

[sail, 2013/02/07 00:46:08]

I don't think this would compile if it was included from a .cc file.

You could fix it by doing something like this:
#ifdef __OBJC__
typedef id<ConstrainedWindowSheet> NativeWebContentsModalDialog;
#else
class ConstrainedWindowSheet;
typedef ConstrainedWindowSheet* NativeWebContentsModalDialog;
#endif

Here's an example:
https://code.google.com/p/chromium/codesearch#chrome/src/ui/gfx/image/image_s...

If this class is never included from a .cc file on Mac then you could just do
something like this instead:

#if defined(OS_MACOSX)
#ifdef __OBJC__
...
#else
#error This header should be included from a .mm file.
#endif

[Mike Wittman, 2013/02/11 22:20:30]

I've updated the ifdefs based on the code in image_skia_util_mac.h.  I'm not
certain this will never be included in a .cc file on Mac.

+typedef id<ConstrainedWindowSheet> NativeWebContentsModalDialog;
+#else
+typedef gfx::NativeWindow NativeWebContentsModalDialog;
+#endif
+
+#endif  // CHROME_BROWSER_UI_NATIVE_WEB_CONTENTS_MODAL_DIALOG_H_