[sessions] Introduce iOS implementation of LiveTab interface

components/sessions/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.
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
 config("implementation") {
   defines = [ "SESSIONS_IMPLEMENTATION" ]
@@ skipping 23 matching lines @@
     deps = [
       "//base",
       "//base/third_party/dynamic_annotations",
       "//ui/base",
       "//url",
     ]
   }
 } else {
   source_set("sessions") {
     sources = [
+      "ios/ios_live_tab.cc",
+      "ios/ios_live_tab.h",
       "ios/ios_serialized_navigation_builder.cc",
       "ios/ios_serialized_navigation_builder.h",
       "ios/ios_serialized_navigation_driver.cc",
       "ios/ios_serialized_navigation_driver.h",
     ]
 
     public_deps = [
       ":shared",
     ]
 
@@ skipping 107 matching lines @@
       "ios/ios_serialized_navigation_driver_unittest.cc",
     ]
     deps = [
       ":sessions",
       ":test_support",
       "//base/test:test_support",
       "//testing/gtest",
     ]
   }
 }