[Offline Pages] Introducing StorageManagerClient interface.

components/offline_pages/BUILD.gn

 # Copyright 2015 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/rules.gni")
 }
 
 # GYP: //components/offline_pages.gypi:offline_pages
 static_library("offline_pages") {
@@ skipping 10 matching lines @@
     "offline_page_metadata_store_impl.h",
     "offline_page_metadata_store_sql.cc",
     "offline_page_metadata_store_sql.h",
     "offline_page_model.cc",
     "offline_page_model.h",
     "offline_page_storage_manager.cc",
     "offline_page_storage_manager.h",
     "offline_page_types.h",
     "snapshot_controller.cc",
     "snapshot_controller.h",
+    "storage_manager_client.h",
   ]
 
   deps = [
     ":switches",
     "//base",
     "//components/bookmarks/browser",
     "//components/keyed_service/core",
     "//components/leveldb_proto",
     "//components/offline_pages/proto:offline_pages_proto",
     "//net",
@@ skipping 56 matching lines @@
   ]
 }
 
 if (is_android) {
   java_cpp_enum("offline_page_model_enums_java") {
     sources = [
       "offline_page_types.h",
     ]
   }
 }