[sessions] Introduce iOS implementation of LiveTab interface

components/sessions.gypi

 # Copyright 2013 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.
 
 {
   'variables': {
     # Core sources shared by sessions_content and sessions_ios. These can't
     # be a separate shared library since one symbol is implemented higher up in
     # the sessions_content/ios layer.
     'sessions_core_sources': [
@@ skipping 129 matching lines @@
           ],
           'include_dirs': [
             '..',
           ],
           'defines': [
             'SESSIONS_IMPLEMENTATION',
           ],
           'sources': [
             '<@(sessions_core_sources)',
 
+            'sessions/ios/ios_live_tab.cc',
+            'sessions/ios/ios_live_tab.h',
             'sessions/ios/ios_serialized_navigation_builder.cc',
             'sessions/ios/ios_serialized_navigation_builder.h',
             'sessions/ios/ios_serialized_navigation_driver.cc',
             'sessions/ios/ios_serialized_navigation_driver.h',
           ],
         },
       ],
     }],
   ],
 
 }