Add most missing blink files to .gn files

third_party/WebKit/Source/modules/storage/BUILD.gn

 # Copyright 2016 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.
 
 import("//third_party/WebKit/Source/modules/modules.gni")
 
 blink_modules_sources("storage") {
   sources = [
     "DOMWindowStorage.cpp",
     "DOMWindowStorage.h",
     "DOMWindowStorageController.cpp",
     "DOMWindowStorageController.h",
     "InspectorDOMStorageAgent.cpp",
     "InspectorDOMStorageAgent.h",
     "Storage.cpp",
     "Storage.h",
     "StorageArea.cpp",
     "StorageArea.h",
+    "StorageClient.h",
     "StorageEvent.cpp",
     "StorageEvent.h",
     "StorageNamespace.cpp",
     "StorageNamespace.h",
     "StorageNamespaceController.cpp",
     "StorageNamespaceController.h",
   ]
 }