[SVG2] Add support for the 'turn' unit in <angle>.

Source/core/svg/SVGAngleTearOff.h

Index: Source/core/svg/SVGAngleTearOff.h
diff --git a/Source/core/svg/SVGAngleTearOff.h b/Source/core/svg/SVGAngleTearOff.h
index 8d6d52084b908acc61113efec7c7ae437ba1a538..bec02c1bf3ecbb00d5082c3ac42e8cb28712fd84 100644
--- a/Source/core/svg/SVGAngleTearOff.h
+++ b/Source/core/svg/SVGAngleTearOff.h
@@ -54,7 +54,7 @@ public:
 
     virtual ~SVGAngleTearOff();
 
-    unsigned short unitType() { return target()->unitType(); }
+    unsigned short unitType() { return isValidAngle() ? target()->unitType() : SVGAngle::SVG_ANGLETYPE_UNKNOWN; }
 
     void setValue(float, ExceptionState&);
     float value() { return target()->value(); }
@@ -65,9 +65,11 @@ public:
     void newValueSpecifiedUnits(unsigned short unitType, float valueInSpecifiedUnits, ExceptionState&);
     void convertToSpecifiedUnits(unsigned short unitType, ExceptionState&);
 
-    String valueAsString() { return target()->valueAsString(); }
+    String valueAsString() { return isValidAngle() ? target()->valueAsString() : String::number(0); }

[krit, 2014/06/10 11:45:48]

Exposing more unit types is one thing. Do we need to be restrictive on
valueAsString? 

[Erik Dahlström (inactive), 2014/06/10 16:57:42]

Not necessarily, only if we want to preserve existing (public) behavior.

The spec is fairly clear on what should happen ("SVGAngle.valueAsString: The
angle value as a string value, in the units expressed by unitType.")

Since unitType is "unknown" the returned string is the default value (0 in this
case).

     void setValueAsString(const String&, ExceptionState&);
 
+    bool isValidAngle() { return target()->unitType() <= SVGAngle::SVG_ANGLETYPE_GRAD; }

[fs, 2014/06/10 11:13:30]

Nit: isValidAngleType / isValidAngleUnit ?

(Could be private and const?)

[Erik Dahlström (inactive), 2014/06/10 16:57:42]

Private yes, const no, the target() method is non-const.

[fs, 2014/06/11 07:29:07]

Ok.

+
 private:
     SVGAngleTearOff(PassRefPtr<SVGAngle>, SVGElement*, PropertyIsAnimValType, const QualifiedName&);
 };