Add missing header files to GN files

chrome/browser/extensions/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/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
 import("//extensions/features/features.gni")
 import("//media/media_options.gni")
 import("//rlz/features/features.gni")
@@ skipping 615 matching lines @@
     "extension_system_impl.cc",
     "extension_system_impl.h",
     "extension_tab_util.cc",
     "extension_tab_util.h",
     "extension_ui_util.cc",
     "extension_ui_util.h",
     "extension_uninstall_dialog.cc",
     "extension_uninstall_dialog.h",
     "extension_util.cc",
     "extension_util.h",
+    "extension_view.h",
     "extension_view_host.cc",
     "extension_view_host.h",
     "extension_view_host_factory.cc",
     "extension_view_host_factory.h",
     "extension_web_ui.cc",
     "extension_web_ui.h",
     "extension_web_ui_override_registrar.cc",
     "extension_web_ui_override_registrar.h",
     "extension_webkit_preferences.cc",
     "extension_webkit_preferences.h",
@@ skipping 541 matching lines @@
       "api/braille_display_private/brlapi_connection.cc",
       "api/braille_display_private/brlapi_connection.h",
       "api/braille_display_private/brlapi_keycode_map.cc",
       "api/braille_display_private/brlapi_keycode_map.h",
     ]
     deps += [ "//build/linux/libbrlapi" ]
   } else {
     sources += [ "api/braille_display_private/braille_controller_stub.cc" ]
   }
 }