Makes browser resize content when root bounds change

mandoline/ui/browser/browser_ui.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 MANDOLINE_UI_BROWSER_BROWSER_UI_H_
 #define MANDOLINE_UI_BROWSER_BROWSER_UI_H_
 
 namespace mojo {
 class Shell;
 class View;
 }
 
 namespace mandoline {
 
 class Browser;
 
 class BrowserUI {
  public:
   virtual ~BrowserUI() {}
   static BrowserUI* Create(Browser* browser, mojo::Shell* shell);
 
   // Called when the Browser UI is embedded within the specified view.
+  // BrowserUI is destroyed prior to |root| being destroyed. That is, the
+  // BrowserUI implementations can assume |root| is never deleted out from under
+  // them.
   virtual void Init(mojo::View* root, mojo::View* content) = 0;
 };
 
 }  // namespace mandoline
 
 #endif  // MANDOLINE_UI_BROWSER_BROWSER_UI_H_