updating Input field value by script should reset IME composition.

third_party/WebKit/Source/core/editing/Editor.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 1737 matching lines @@
 
   are_marked_text_matches_highlighted_ = flag;
   GetFrame().GetDocument()->Markers().RepaintMarkers(
       DocumentMarker::kTextMatch);
 }
 
 void Editor::RespondToChangedSelection(
     const Position& old_selection_start,
     FrameSelection::SetSelectionOptions options) {
   GetSpellChecker().RespondToChangedSelection(old_selection_start, options);
+  GetFrame().GetInputMethodController().CancelCompositionIfSelectionIsInvalid();
   Client().RespondToChangedSelection(&GetFrame(),
                                      GetFrame()
                                          .Selection()
                                          .GetSelectionInDOMTree()
                                          .SelectionTypeWithLegacyGranularity());
   SetStartNewKillRingSequence(true);
 }
 
 SpellChecker& Editor::GetSpellChecker() const {
   return GetFrame().GetSpellChecker();
@@ skipping 69 matching lines @@
 
 DEFINE_TRACE(Editor) {
   visitor->Trace(frame_);
   visitor->Trace(last_edit_command_);
   visitor->Trace(undo_stack_);
   visitor->Trace(mark_);
   visitor->Trace(typing_style_);
 }
 
 }  // namespace blink