Create a spellcheck component that will allow any embedder to reuse common functionality.

components/spellcheck/common/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("//build/config/features.gni")
+
+# GYP: components.gyp:spellcheck_common
+if (enable_spellcheck) {
+  source_set("common") {
+    sources = [
+      "spellcheck_bdict_language.h",
+      "spellcheck_marker.h",
+      "spellcheck_message.h",
+      "spellcheck_result.h",
+    ]
+    deps = [
+      "//base",
+      "//ipc",
+    ]
+  }
+}