[MacViews] Implement AlwaysOnTop and VisibleOnAllWorkspaces.

ui/gfx/mac/nswindow_frame_controls.h

 // Copyright 2015 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 UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_
 #define UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_
 
 #include "ui/gfx/gfx_export.h"
 
 @class NSWindow;
 
 namespace gfx {
 
 class Size;
 
 // Set whether the window can be fullscreened.
 GFX_EXPORT void SetNSWindowCanFullscreen(NSWindow* window,
                                          bool allow_fullscreen);
 
+// Returns whether the window is always-on-top.
+GFX_EXPORT bool IsNSWindowAlwaysOnTop(NSWindow* window);
+
+// Sets whether the window is always-on-top. This also sets
+// NSWindowCollectionBehaviorManaged because by default always-on-top windows
+// are NSWindowCollectionBehaviorTransient which means they will not appear in
+// Expose and cannot be moved between workspaces.
+GFX_EXPORT void SetNSWindowAlwaysOnTop(NSWindow* window,
+                                       bool always_on_top);
+
+// Sets whether the window appears on all workspaces.
+GFX_EXPORT void SetNSWindowVisibleOnAllWorkspaces(NSWindow* window,
+                                                  bool always_visible);
+
 // Sets the min/max size of the window as well as showing/hiding resize,
 // maximize, and fullscreen controls.
 // Sizes refer to the content size (inner bounds).
 GFX_EXPORT void ApplyNSWindowSizeConstraints(NSWindow* window,
                                              const gfx::Size& min_size,
                                              const gfx::Size& max_size,
                                              bool can_resize,
                                              bool can_fullscreen);
 
 }  // namespace gfx
 
 #endif  // UI_GFX_MAC_NSWINDOW_FRAME_CONTROLS_H_