Do not use setInnerText in INPUT / TEXTAREA

third_party/WebKit/Source/core/html/HTMLTextFormControlElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 20 matching lines @@
 #include "core/dom/Document.h"
 #include "core/dom/ElementTraversal.h"
 #include "core/dom/NodeList.h"
 #include "core/dom/Text.h"
 #include "core/dom/shadow/ShadowRoot.h"
 #include "core/editing/EditingUtilities.h"
 #include "core/editing/Editor.h"
 #include "core/editing/FrameSelection.h"
 #include "core/editing/iterators/CharacterIterator.h"
 #include "core/editing/iterators/TextIterator.h"
+#include "core/editing/serializers/Serialization.h"
 #include "core/events/Event.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/UseCounter.h"
 #include "core/html/HTMLBRElement.h"
 #include "core/html/shadow/ShadowElementNames.h"
 #include "core/layout/LayoutBlock.h"
 #include "core/layout/LayoutBlockFlow.h"
 #include "core/layout/LayoutTheme.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
@@ skipping 577 matching lines @@
     bool textIsChanged = value != innerEditorValue();
     HTMLElement* innerEditor = innerEditorElement();
     if (!textIsChanged && innerEditor->hasChildren())
         return;
 
     // If the last child is a trailing <br> that's appended below, remove it
     // first so as to enable setInnerText() fast path of updating a text node.
     if (isHTMLBRElement(innerEditor->lastChild()))
         innerEditor->removeChild(innerEditor->lastChild(), ASSERT_NO_EXCEPTION);
 
-    innerEditor->setInnerText(value, ASSERT_NO_EXCEPTION);
+    // We don't use setTextContent.  It triggers unnecessary paint.
+    if (value.isEmpty())

[tkent, 2016/03/10 00:57:02]

I added this code after yosin's lgtm.  Both of setInnerText and setTextContent
have this logic.

 if (value.isEmpty())
     innerEditor->removeChildren();
 else
     replaceChildrenWithText(...)

+        innerEditor->removeChildren();
+    else
+        replaceChildrenWithText(innerEditor, value, ASSERT_NO_EXCEPTION);
 
     if (value.endsWith('\n') || value.endsWith('\r'))
         innerEditor->appendChild(HTMLBRElement::create(document()));
 
     if (textIsChanged && layoutObject()) {
         if (AXObjectCache* cache = document().existingAXObjectCache())
             cache->handleTextFormControlChanged(this);
     }
 }
 
@@ skipping 360 matching lines @@
 }
 
 void HTMLTextFormControlElement::copyNonAttributePropertiesFromElement(const Element& source)
 {
     const HTMLTextFormControlElement& sourceElement = static_cast<const HTMLTextFormControlElement&>(source);
     m_lastChangeWasUserEdit = sourceElement.m_lastChangeWasUserEdit;
     HTMLFormControlElement::copyNonAttributePropertiesFromElement(source);
 }
 
 } // namespace blink