[css-typed-om] make all attributes of CSSScale mutable.

third_party/WebKit/Source/core/css/cssom/CSSScale.h

Index: third_party/WebKit/Source/core/css/cssom/CSSScale.h
diff --git a/third_party/WebKit/Source/core/css/cssom/CSSScale.h b/third_party/WebKit/Source/core/css/cssom/CSSScale.h
index 8f509db59fa1705c55bbf048dd2944a4537b02ba..5f155687d6cce04b4e155f2bb07bb563309694d6 100644
--- a/third_party/WebKit/Source/core/css/cssom/CSSScale.h
+++ b/third_party/WebKit/Source/core/css/cssom/CSSScale.h
@@ -27,6 +27,10 @@ class CORE_EXPORT CSSScale final : public CSSTransformComponent {
   double y() const { return y_; }
   double z() const { return z_; }
 
+  void setX(double x) { x_ = x; }
+  void setY(double y) { y_ = y; }
+  void setZ(double z) { z_ = z; }
+
   TransformComponentType GetType() const override {
     return is2d_ ? kScaleType : kScale3DType;
   }