Add a skeleton of idle time spell checker

third_party/WebKit/Source/core/editing/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/core/core.gni")
 
 blink_core_sources("editing") {
   split_count = 5
   sources = [
     "CaretBase.cpp",
@@ skipping 159 matching lines @@
     "serializers/MarkupFormatter.cpp",
     "serializers/MarkupFormatter.h",
     "serializers/Serialization.cpp",
     "serializers/Serialization.h",
     "serializers/StyledMarkupAccumulator.cpp",
     "serializers/StyledMarkupAccumulator.h",
     "serializers/StyledMarkupSerializer.cpp",
     "serializers/StyledMarkupSerializer.h",
     "serializers/TextOffset.cpp",
     "serializers/TextOffset.h",
+    "spellcheck/IdleSpellCheckCallback.cpp",
+    "spellcheck/IdleSpellCheckCallback.h",
     "spellcheck/SpellCheckRequester.cpp",
     "spellcheck/SpellCheckRequester.h",
     "spellcheck/SpellChecker.cpp",
     "spellcheck/SpellChecker.h",
     "spellcheck/TextCheckingParagraph.cpp",
     "spellcheck/TextCheckingParagraph.h",
     "state_machines/BackspaceStateMachine.cpp",
     "state_machines/BackspaceStateMachine.h",
     "state_machines/BackwardGraphemeBoundaryStateMachine.cpp",
     "state_machines/BackwardGraphemeBoundaryStateMachine.h",
@@ skipping 66 matching lines @@
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]
 
   deps = [
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/WebKit/Source/core:core",
   ]
 }