Restore logic to unsubscribe from permission changes on frame change.

content/browser/permissions/permission_service_context.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 CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_CONTEXT_H_
 #define CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_CONTEXT_H_
 
 #include "base/macros.h"
 #include "base/memory/scoped_vector.h"
 #include "content/public/browser/permission_type.h"
@@ skipping 52 matching lines @@
   class PermissionSubscription;
 
   // WebContentsObserver
   void RenderFrameHostChanged(RenderFrameHost* old_host,
                               RenderFrameHost* new_host) override;
   void FrameDeleted(RenderFrameHost* render_frame_host) override;
   void DidNavigateAnyFrame(RenderFrameHost* render_frame_host,
                            const LoadCommittedDetails& details,
                            const FrameNavigateParams& params) override;
 
-  void CancelPendingOperations(RenderFrameHost*) const;
+  void CancelPendingOperations(RenderFrameHost*);
 
   RenderFrameHost* render_frame_host_;
   RenderProcessHost* render_process_host_;
   std::vector<std::unique_ptr<PermissionServiceImpl>> services_;
   std::unordered_map<int, std::unique_ptr<PermissionSubscription>>
       subscriptions_;
 
   DISALLOW_COPY_AND_ASSIGN(PermissionServiceContext);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_PERMISSIONS_PERMISSION_SERVICE_CONTEXT_H_