Make InsertIncrementalTextCommand to handle surrogate pair

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 254 matching lines @@
     "SelectionControllerTest.cpp",
     "SelectionTemplateTest.cpp",
     "SurroundingTextTest.cpp",
     "VisiblePositionTest.cpp",
     "VisibleSelectionTest.cpp",
     "VisibleUnitsTest.cpp",
     "commands/ApplyBlockElementCommandTest.cpp",
     "commands/ApplyStyleCommandTest.cpp",
     "commands/CompositeEditCommandTest.cpp",
     "commands/DeleteSelectionCommandTest.cpp",
+    "commands/InsertIncrementalTextCommandTest.cpp",
     "commands/InsertListCommandTest.cpp",
     "commands/ReplaceSelectionCommandTest.cpp",
     "commands/SetCharacterDataCommandTest.cpp",
     "commands/TypingCommandTest.cpp",
     "iterators/BackwardsTextBufferTest.cpp",
     "iterators/CharacterIteratorTest.cpp",
     "iterators/ForwardsTextBufferTest.cpp",
     "iterators/SearchBufferTest.cpp",
     "iterators/SimplifiedBackwardsTextIteratorTest.cpp",
     "iterators/TextIteratorTest.cpp",
@@ skipping 20 matching lines @@
     "//third_party/WebKit/Source:config",
     "//third_party/WebKit/Source:inside_blink",
   ]
 
   deps = [
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/WebKit/Source/core:core",
   ]
 }