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

chrome/browser/ui/BUILD.gn

 # 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.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 1737 matching lines @@
         "views/location_bar/keyword_hint_view.cc",
         "views/location_bar/keyword_hint_view.h",
         "views/location_bar/location_bar_decoration_view.cc",
         "views/location_bar/location_bar_decoration_view.h",
         "views/location_bar/location_bar_layout.cc",
         "views/location_bar/location_bar_layout.h",
         "views/location_bar/location_bar_view.cc",
         "views/location_bar/location_bar_view.h",
         "views/location_bar/location_icon_view.cc",
         "views/location_bar/location_icon_view.h",
-        "views/location_bar/open_pdf_in_reader_view.cc",
-        "views/location_bar/open_pdf_in_reader_view.h",
         "views/location_bar/page_action_image_view.cc",
         "views/location_bar/page_action_image_view.h",
         "views/location_bar/page_action_with_badge_view.cc",
         "views/location_bar/page_action_with_badge_view.h",
         "views/location_bar/selected_keyword_view.cc",
         "views/location_bar/selected_keyword_view.h",
         "views/location_bar/star_view.cc",
         "views/location_bar/star_view.h",
         "views/location_bar/zoom_bubble_view.cc",
         "views/location_bar/zoom_bubble_view.h",
         "views/location_bar/zoom_view.cc",
         "views/location_bar/zoom_view.h",
         "views/omnibox/omnibox_popup_contents_view.cc",
         "views/omnibox/omnibox_popup_contents_view.h",
         "views/omnibox/omnibox_result_view.cc",
         "views/omnibox/omnibox_result_view.h",
         "views/omnibox/omnibox_view_views.cc",
         "views/omnibox/omnibox_view_views.h",
-        "views/open_pdf_in_reader_bubble_view.cc",
-        "views/open_pdf_in_reader_bubble_view.h",
         "views/outdated_upgrade_bubble_view.cc",
         "views/outdated_upgrade_bubble_view.h",
         "views/passwords/account_chooser_dialog_view.cc",
         "views/passwords/account_chooser_dialog_view.h",
         "views/passwords/auto_signin_first_run_dialog_view.cc",
         "views/passwords/auto_signin_first_run_dialog_view.h",
         "views/passwords/credentials_item_view.cc",
         "views/passwords/credentials_item_view.h",
         "views/passwords/credentials_selection_view.cc",
         "views/passwords/credentials_selection_view.h",
@@ skipping 1713 matching lines @@
       "test/test_confirm_bubble_model.cc",
       "test/test_confirm_bubble_model.h",
     ]
     deps += [ "//chrome/test:test_support_ui" ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }