Remove dead code since PDFWebContentsHelper::ShowOpenInReaderPrompt isn't called anymore.

chrome/browser/ui/cocoa/location_bar/location_bar_view_mac.h

 // Copyright (c) 2012 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_COCOA_LOCATION_BAR_LOCATION_BAR_VIEW_MAC_H_
 #define CHROME_BROWSER_UI_COCOA_LOCATION_BAR_LOCATION_BAR_VIEW_MAC_H_
 
 #import <Cocoa/Cocoa.h>
 #include <stddef.h>
 
@@ skipping 52 matching lines @@
   void FocusLocation(bool select_all) override;
   void FocusSearch() override;
   void UpdateContentSettingsIcons() override;
   void UpdateManagePasswordsIconAndBubble() override;
   void UpdateSaveCreditCardIcon() override;
   void UpdatePageActions() override;
   void UpdateBookmarkStarVisibility() override;
   void UpdateLocationBarVisibility(bool visible, bool animate) override;
   bool ShowPageActionPopup(const extensions::Extension* extension,
                            bool grant_active_tab) override;
-  void UpdateOpenPDFInReaderPrompt() override;
   void SaveStateToContents(content::WebContents* contents) override;
   void Revert() override;
   const OmniboxView* GetOmniboxView() const override;
   OmniboxView* GetOmniboxView() override;
   LocationBarTesting* GetLocationBarForTesting() override;
 
   // Overridden from LocationBarTesting:
   int PageActionCount() override;
   int PageActionVisibleCount() override;
   ExtensionAction* GetPageAction(size_t index) override;
@@ skipping 249 matching lines @@
   // The security level of the location bar icon.
   security_state::SecurityLevel security_level_;
 
   // Used to schedule a task for the first run info bubble.
   base::WeakPtrFactory<LocationBarViewMac> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(LocationBarViewMac);
 };
 
 #endif  // CHROME_BROWSER_UI_COCOA_LOCATION_BAR_LOCATION_BAR_VIEW_MAC_H_