Revert r154797: "Move isValid/isCurrentColor from Color to StyleColor"

Source/core/css/SVGCSSComputedStyleDeclaration.cpp

Index: Source/core/css/SVGCSSComputedStyleDeclaration.cpp
diff --git a/Source/core/css/SVGCSSComputedStyleDeclaration.cpp b/Source/core/css/SVGCSSComputedStyleDeclaration.cpp
index 166a2f25231f25e4281897e778fe3dc3ff2a0c61..5858b4813159fbf607418b5f3912bfff4f39f8e3 100644
--- a/Source/core/css/SVGCSSComputedStyleDeclaration.cpp
+++ b/Source/core/css/SVGCSSComputedStyleDeclaration.cpp
@@ -83,11 +83,8 @@ static PassRefPtr<CSSValue> paintOrderToCSSValueList(EPaintOrder paintorder)
 PassRefPtr<SVGPaint> CSSComputedStyleDeclaration::adjustSVGPaintForCurrentColor(PassRefPtr<SVGPaint> newPaint, RenderStyle* style) const
 {
     RefPtr<SVGPaint> paint = newPaint;
-    if (paint->paintType() == SVGPaint::SVG_PAINTTYPE_CURRENTCOLOR || paint->paintType() == SVGPaint::SVG_PAINTTYPE_URI_CURRENTCOLOR) {
-        // SVG handles currentColor itself, style->color() is guaranteed not to be currentColor.
-        ASSERT(!style->color().isCurrentColor());
-        paint->setColor(style->color().color());
-    }
+    if (paint->paintType() == SVGPaint::SVG_PAINTTYPE_CURRENTCOLOR || paint->paintType() == SVGPaint::SVG_PAINTTYPE_URI_CURRENTCOLOR)
+        paint->setColor(style->color());
     return paint.release();
 }