Make PermissionRequestManager::requests_ correspond to the active prompt

chrome/browser/ui/permission_bubble/permission_prompt.h

 // 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.
 
 #ifndef CHROME_BROWSER_UI_PERMISSION_BUBBLE_PERMISSION_PROMPT_H_
 #define CHROME_BROWSER_UI_PERMISSION_BUBBLE_PERMISSION_PROMPT_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 51 matching lines @@
   // is being shown and the mouse is not over the view area (!IsMouseHovered).
   virtual bool CanAcceptRequestUpdate() = 0;
 
   // Returns true if the prompt UI will manage hiding itself when the user
   // resolves the prompt, on page navigation/destruction, and on tab switching.
   virtual bool HidesAutomatically() = 0;
 
   // Hides the permission prompt.
   virtual void Hide() = 0;
 
-  // Returns true if there is a prompt currently showing.
-  virtual bool IsVisible() = 0;
-
   // Updates where the prompt should be anchored. ex: fullscreen toggle.
   virtual void UpdateAnchorPosition() = 0;
 
   // Returns a reference to this prompt's native window.
   // TODO(hcarmona): Remove this as part of the bubble API work.
   virtual gfx::NativeWindow GetNativeWindow() = 0;
 };
 
 #endif  // CHROME_BROWSER_UI_PERMISSION_BUBBLE_PERMISSION_PROMPT_H_