Make font-size-adjust animatable.

Source/core/animation/css/CSSAnimatableValueFactory.cpp

Index: Source/core/animation/css/CSSAnimatableValueFactory.cpp
diff --git a/Source/core/animation/css/CSSAnimatableValueFactory.cpp b/Source/core/animation/css/CSSAnimatableValueFactory.cpp
index 98229f58438b67c0ac6e00bf172bd3b3679372b3..1549a48c8f83e4240d989906f9fc1568bf841c5b 100644
--- a/Source/core/animation/css/CSSAnimatableValueFactory.cpp
+++ b/Source/core/animation/css/CSSAnimatableValueFactory.cpp
@@ -379,6 +379,8 @@ PassRefPtrWillBeRawPtr<AnimatableValue> CSSAnimatableValueFactory::create(CSSPro
         // 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: