Decompose //extensions/browser/BUILD.gn

extensions/browser/value_store/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.
+
+source_set("value_store") {
+  sources = [
+    "lazy_leveldb.cc",
+    "lazy_leveldb.h",
+    "legacy_value_store_factory.cc",
+    "legacy_value_store_factory.h",
+    "leveldb_scoped_database.cc",
+    "leveldb_scoped_database.h",
+    "leveldb_value_store.cc",
+    "leveldb_value_store.h",
+    "test_value_store_factory.cc",
+    "test_value_store_factory.h",
+    "testing_value_store.cc",
+    "testing_value_store.h",
+    "value_store.cc",
+    "value_store.h",
+    "value_store_change.cc",
+    "value_store_change.h",
+    "value_store_factory.h",
+    "value_store_factory_impl.cc",
+    "value_store_factory_impl.h",
+    "value_store_frontend.cc",
+    "value_store_frontend.h",
+  ]
+
+  deps = [
+    "//third_party/leveldatabase",
+  ]
+}