Refactor: Untangle Mac's ExclusiveAccessContext from BrowserWindow

chrome/browser/ui/exclusive_access/exclusive_access_context.h

 // Copyright (c) 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 CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_
 #define CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_
 
 #include "build/build_config.h"
 #include "chrome/browser/ui/exclusive_access/exclusive_access_bubble_type.h"
 
@@ skipping 25 matching lines @@
   // fullscreen.
   // Currently only supported on Mac.
   virtual void UpdateFullscreenWithToolbar(bool with_toolbar);
 
   // Toggles the toolbar state to be hidden or shown in fullscreen.
   // Currently only supported on Mac.
   virtual void ToggleFullscreenToolbar();
 
   // Returns true if the window is fullscreen with additional UI elements. See
   // EnterFullscreen |with_toolbar|.
-  virtual bool IsFullscreenWithToolbar() const = 0;
+  virtual bool IsFullscreenWithToolbar() const;
 
   // Enters fullscreen and update exit bubble.
   // On Mac, the tab strip and toolbar will be shown if |with_toolbar| is true,
   // |with_toolbar| is ignored on other platforms.
   virtual void EnterFullscreen(const GURL& url,
                                ExclusiveAccessBubbleType bubble_type,
                                bool with_toolbar) = 0;
 
   // Exits fullscreen and update exit bubble.
   virtual void ExitFullscreen() = 0;
@@ skipping 16 matching lines @@
 #endif  // defined(OS_WIN)
 
   // Returns the currently active WebContents, or nullptr if there is none.
   virtual content::WebContents* GetActiveWebContents() = 0;
 
   // TODO(sriramsr): This is abstraction violation as the following two function
   // does not apply to a platform app window. Ideally, the BrowserView should
   // hide/unhide its download shelf widget when it is instructed to enter/exit
   // fullscreen mode.
   // Displays the download shelf associated with currently active window.
-  virtual void UnhideDownloadShelf();
+  virtual void UnhideDownloadShelf() = 0;
 
   // Hides download shelf associated with currently active window.
-  virtual void HideDownloadShelf();
+  virtual void HideDownloadShelf() = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_EXCLUSIVE_ACCESS_EXCLUSIVE_ACCESS_CONTEXT_H_