Abstract content::SessionStorageNamespace from core TabRestore code

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" ]
 }
 
 if (!is_ios) {
   # GYP version: components/sessions.gypi:sessions_content
   component("sessions") {
     sources = [
       "content/content_serialized_navigation_builder.cc",
       "content/content_serialized_navigation_builder.h",
       "content/content_serialized_navigation_driver.cc",
       "content/content_serialized_navigation_driver.h",
+      "content/content_tab_client_data.cc",
+      "content/content_tab_client_data.h",
     ]
 
     configs += [ ":implementation" ]
 
     public_deps = [
       ":shared",
     ]
 
     deps = [
       ":shared",
@@ skipping 106 matching lines @@
     ]
     deps = [
       ":sessions",
       ":test_support",
       "//base/test:test_support",
       "//testing/gtest",
       "//third_party/protobuf:protobuf_lite",
     ]
   }
 }