Make font-size-adjust animatable.

Source/core/animation/css/CSSAnimatableValueFactory.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 361 matching lines @@
     case CSSPropertyFloodColor:
         return createFromColor(property, style);
     case CSSPropertyFloodOpacity:
         return createFromDouble(style.floodOpacity());
     case CSSPropertyFontSize:
         // Must pass a specified size to setFontSize if Text Autosizing is enabled, but a computed size
         // if text zoom is enabled (if neither is enabled it's irrelevant as they're probably the same).
         // FIXME: Should we introduce an option to pass the computed font size here, allowing consumers to
         // enable text zoom rather than Text Autosizing? See http://crbug.com/227545.
         return createFromDouble(style.specifiedFontSize());
+    case CSSPropertyFontSizeAdjust:
+        return createFromDouble(style.fontSizeAdjust());

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

Shouldn't you use the font's aspect value for 0 to get a smooth transition from
'none' to to <number>?

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

It takes some time to understand this comment. Current implementation is
somewhat different from Gecko's behavior.
Gecko doesn't let font-size-adjust animate for 0 or none as you pointed out. But
I think this is something that needs more general approach for keyframe
animation.
For 'perspective' css property, it also shows us different behavior from Gecko's
where any keyframe has 'none' or unexpected value for the property value.
@-webkit-keyframes fontPerspective {                                            
                                   
  from { -webkit-perspective: none; }                                         
  to { -webkit-perspective: 100px; }                                          
}
This keyframe(or course, unprefixed one used for gecko) doesn't work for gecko,
but blink does.

In short, the animation for unexpected value happens for not only
font-size-adjust, but other properties. How about dealing with the issue in a
seperated ticket?

[Eric Willigers, 2015/03/08 07:10:15]

As it happens, I have a change involving perspective up for review.
https://codereview.chromium.org/955863002

(We are deprecating the AnimatableValue classes and implementing
InterpolableValues. Unfortunately, we still need AnimatableValue classes for
now, e.g. they are currently still used by CSS transitions.)


I had noted the unfortunate behavior regarding 'none' in my change description,
and included a layout test FIXME:
// FIXME: flip between length and none (as Firefox does).


font-size-adjust should also flip - at minimum this should be noted with a
FIXME.

     case CSSPropertyFontStretch:
         return createFromFontStretch(style.fontStretch());
     case CSSPropertyFontWeight:
         return createFromFontWeight(style.fontWeight());
     case CSSPropertyHeight:
         return createFromLength(style.height(), style);
     case CSSPropertyLightingColor:
         return createFromColor(property, style);
     case CSSPropertyListStyleImage:
         return createFromStyleImage(style.listStyleImage());
@@ skipping 147 matching lines @@
     case CSSPropertyZIndex:
         return createFromDouble(style.zIndex());
     default:
         ASSERT_NOT_REACHED();
         // This return value is to avoid a release crash if possible.
         return AnimatableUnknown::create(nullptr);
     }
 }
 
 } // namespace blink