Move TextIteratorTextNodeHandler to dedicated files

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 = [
     "CaretDisplayItemClient.cpp",
@@ skipping 167 matching lines @@
     "iterators/SearchBuffer.cpp",
     "iterators/SearchBuffer.h",
     "iterators/SimplifiedBackwardsTextIterator.cpp",
     "iterators/SimplifiedBackwardsTextIterator.h",
     "iterators/TextBufferBase.cpp",
     "iterators/TextBufferBase.h",
     "iterators/TextIterator.cpp",
     "iterators/TextIterator.h",
     "iterators/TextIteratorBehavior.cpp",
     "iterators/TextIteratorBehavior.h",
+    "iterators/TextIteratorTextNodeHandler.cpp",
+    "iterators/TextIteratorTextNodeHandler.h",
     "iterators/TextIteratorTextState.cpp",
     "iterators/TextIteratorTextState.h",
     "iterators/TextSearcherICU.cpp",
     "iterators/TextSearcherICU.h",
     "iterators/WordAwareIterator.cpp",
     "iterators/WordAwareIterator.h",
     "markers/CompositionMarkerListImpl.cpp",
     "markers/CompositionMarkerListImpl.h",
     "markers/DocumentMarker.cpp",
     "markers/DocumentMarker.h",
@@ skipping 133 matching lines @@
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]
 
   deps = [
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/WebKit/Source/core:core",
   ]
 }