Printing: Keep track of WebContents lifetime for the native printing UI.

chrome/chrome_browser.gypi

 # Copyright 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
       'variables': { 'enable_wexit_time_destructors': 1, },
@@ skipping 1680 matching lines @@
         'browser/printing/print_view_manager.h',
         'browser/printing/print_view_manager_observer.h',
         'browser/printing/printer_manager_dialog.h',
         'browser/printing/printer_manager_dialog_linux.cc',
         'browser/printing/printer_manager_dialog_mac.mm',
         'browser/printing/printer_manager_dialog_win.cc',
         'browser/printing/printer_query.cc',
         'browser/printing/printer_query.h',
         'browser/printing/printing_message_filter.cc',
         'browser/printing/printing_message_filter.h',
+        'browser/printing/printing_ui_web_contents_observer.cc',
+        'browser/printing/printing_ui_web_contents_observer.h',
         'browser/process_info_snapshot.h',
         'browser/process_info_snapshot_mac.cc',
         'browser/process_singleton.h',
         'browser/process_singleton_linux.cc',
         'browser/process_singleton_mac.cc',
         'browser/process_singleton_modal_dialog_lock.cc',
         'browser/process_singleton_modal_dialog_lock.h',
         'browser/process_singleton_startup_lock.cc',
         'browser/process_singleton_startup_lock.h',
         'browser/process_singleton_win.cc',
@@ skipping 1979 matching lines @@
             'package_name': 'org/chromium/chrome/browser/ui/toolbar',
             'template_deps': ['browser/ui/toolbar/toolbar_model_security_level_list.h'],
           },
           'includes': [ '../build/android/java_cpp_template.gypi' ],
         },
       ],
      },
     ],
   ],
 }