Make font-size-adjust animatable.

Source/core/css/resolver/FontBuilder.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Google Inc. All rights reserved.
  * Copyright (C) 2015 Collabora Ltd. All rights reserved.
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
@@ skipping 317 matching lines @@
 }
 
 void FontBuilder::updateAdjustedSize(FontDescription& fontDescription, const LayoutStyle& style, FontSelector* fontSelector)
 {
     const float sizeAdjust = fontDescription.sizeAdjust();
     const float specifiedSize = fontDescription.specifiedSize();
     if (!sizeAdjust || !specifiedSize)
         return;
 
     // We need to create a temporal Font to get xHeight of a primary font.
+    // To get an accurate x-height from a font cache while animation, we need to reset adjustedSize

[rune, 2015/03/06 10:08:06]

... while animating ...

[changseok, 2015/03/08 06:16:56]

Done.

+    // before creating a Font. Because a retrived font data from the cache is based on a FontCacheKey
+    // and which is affected by effectiveFontSize.

[rune, 2015/03/06 10:08:05]

-and

[changseok, 2015/03/08 06:16:56]

Done.

+    fontDescription.setAdjustedSize(0);

[rune, 2015/03/06 10:08:06]

This is necessary in general to get the correct result when calling
updateFont(), hence createFont(), multiple times on the same FontBuilder. This
happens to be the case for animations only at the moment, but the comment should
probably say something along the lines of:

"The aspect value is based on the x-height of the font for the computed font
size, so we need to reset the adjustment."

Would that be correct?

[changseok, 2015/03/08 06:16:56]

Yes correct. thanks for the summary =)

+
     Font font(fontDescription);
     font.update(fontSelector);
     if (!font.fontMetrics().hasXHeight())
         return;
 
     float aspectValue = font.fontMetrics().xHeight() / specifiedSize;
     float adjustedSize = (sizeAdjust / aspectValue) * specifiedSize;
     adjustedSize = getComputedSizeFromSpecifiedSize(fontDescription, style.effectiveZoom(), adjustedSize);
 
     float multiplier = style.textAutosizingMultiplier();
@@ skipping 77 matching lines @@
     FontOrientation fontOrientation;
     NonCJKGlyphOrientation glyphOrientation;
     getFontAndGlyphOrientation(documentStyle, fontOrientation, glyphOrientation);
     fontDescription.setOrientation(fontOrientation);
     fontDescription.setNonCJKGlyphOrientation(glyphOrientation);
     documentStyle.setFontDescription(fontDescription);
     documentStyle.font().update(fontSelector);
 }
 
 }