Use StringBuilder::appendLiteral() / StringBuilder::append(char) when possible

Source/core/rendering/RenderText.cpp

 /*
  * (C) 1999 Lars Knoll (knoll@kde.org)
  * (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2006 Graham Dennis (graham.dennis@gmail.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 300 matching lines @@
 {
     if (node())
         return blink::plainText(rangeOfContents(node()).get());
 
     // FIXME: this is just a stopgap until TextIterator is adapted to support generated text.
     StringBuilder plainTextBuilder;
     for (InlineTextBox* textBox = firstTextBox(); textBox; textBox = textBox->nextTextBox()) {
         String text = m_text.substring(textBox->start(), textBox->len()).simplifyWhiteSpace(WTF::DoNotStripWhiteSpace);
         plainTextBuilder.append(text);
         if (textBox->nextTextBox() && textBox->nextTextBox()->start() > textBox->end() && text.length() && !text.right(1).containsOnlyWhitespace())
-            plainTextBuilder.append(" ");
+            plainTextBuilder.append(' ');
     }
     return plainTextBuilder.toString();
 }
 
 void RenderText::absoluteRects(Vector<IntRect>& rects, const LayoutPoint& accumulatedOffset) const
 {
     for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
         rects.append(enclosingIntRect(FloatRect(accumulatedOffset + box->topLeft(), box->size())));
 }
 
@@ skipping 1540 matching lines @@
     }
     secureTextTimer->restartWithNewText(lastTypedCharacterOffset);
 }
 
 PassRefPtr<AbstractInlineTextBox> RenderText::firstAbstractInlineTextBox()
 {
     return AbstractInlineTextBox::getOrCreate(this, m_firstTextBox);
 }
 
 } // namespace blink