Add unit test for GlyphPageTreeNode.

Source/platform/fonts/GlyphPage.h

 /*
  * Copyright (C) 2006, 2007, 2008, 2013 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
  *
  * 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.
@@ skipping 156 matching lines @@
         for (size_t i = 0; i < size; ++i) {
             if (m_perGlyphFontData[i] == fontData) {
                 m_glyphs[i] = 0;
                 m_perGlyphFontData[i] = 0;
             }
         }
     }
 
     GlyphPageTreeNode* owner() const { return m_owner; }
 
-    // Implemented by the platform.
-    bool fill(unsigned offset, unsigned length, UChar* characterBuffer, unsigned bufferLength, const SimpleFontData*);
-
 private:
     explicit GlyphPage(GlyphPageTreeNode* owner, const SimpleFontData* fontDataForAllGlyphs = 0)
         : m_fontDataForAllGlyphs(fontDataForAllGlyphs)
         , m_owner(owner)
     {
         memset(m_glyphs, 0, sizeof(m_glyphs));
         if (hasPerGlyphFontData())
             memset(m_perGlyphFontData, 0, sizeof(SimpleFontData*) * GlyphPage::size);
     }
 
     bool hasPerGlyphFontData() const { return !m_fontDataForAllGlyphs; }
 
     const SimpleFontData* m_fontDataForAllGlyphs;
     GlyphPageTreeNode* m_owner;
     Glyph m_glyphs[size];
 
     // NOTE: This array has (GlyphPage::size) elements if m_fontDataForAllGlyphs is null.
     const SimpleFontData* m_perGlyphFontData[0];
 };
 
 #if COMPILER(MSVC)
 #pragma warning(pop)
 #endif
 
 } // namespace WebCore
 
 #endif // GlyphPage_h