Improve robustness of RenderCombine emphasis mark replacement character

Source/core/rendering/TextPainter.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 #include "core/rendering/TextPainter.h"
 
 #include "core/CSSPropertyNames.h"
 #include "core/frame/Settings.h"
 #include "core/rendering/InlineTextBox.h"
@@ skipping 205 matching lines @@
         if (endOffset > 0)
             paintInternalRun<Step>(textRunPaintInfo, 0, endOffset);
         if (startOffset < truncationPoint)
             paintInternalRun<Step>(textRunPaintInfo, startOffset, truncationPoint);
     }
 }
 
 void TextPainter::paintEmphasisMarkForCombinedText()
 {
     ASSERT(m_combinedText);
-    DEFINE_STATIC_LOCAL(TextRun, objectReplacementCharacterTextRun, (&objectReplacementCharacter, 1));
-    FloatPoint emphasisMarkTextOrigin(m_textBounds.x() + m_textBounds.width() / 2, m_textBounds.y() + m_font.fontMetrics().ascent() + m_emphasisMarkOffset);
-    TextRunPaintInfo textRunPaintInfo(objectReplacementCharacterTextRun);
+    DEFINE_STATIC_LOCAL(TextRun, placeholderTextRun, (&ideographicFullStop, 1));
+    FloatPoint emphasisMarkTextOrigin(m_textBounds.x(), m_textBounds.y() + m_font.fontMetrics().ascent() + m_emphasisMarkOffset);
+    TextRunPaintInfo textRunPaintInfo(placeholderTextRun);
     textRunPaintInfo.bounds = m_textBounds;
     m_graphicsContext->concatCTM(InlineTextBox::rotation(m_textBounds, InlineTextBox::Clockwise));
     m_graphicsContext->drawEmphasisMarks(m_combinedText->originalFont(), textRunPaintInfo, m_emphasisMark, emphasisMarkTextOrigin);
     m_graphicsContext->concatCTM(InlineTextBox::rotation(m_textBounds, InlineTextBox::Counterclockwise));
 }
 
 } // namespace blink