Move isValid/isCurrentColor from Color to StyleColor

Source/core/html/track/TextTrackCueGeneric.h

Index: Source/core/html/track/TextTrackCueGeneric.h
diff --git a/Source/core/html/track/TextTrackCueGeneric.h b/Source/core/html/track/TextTrackCueGeneric.h
index 4997e86ff3b6bea343b2c551df36a39f6ec214d4..39ba418a9c09f734e418f01fc529dc59fae7724e 100644
--- a/Source/core/html/track/TextTrackCueGeneric.h
+++ b/Source/core/html/track/TextTrackCueGeneric.h
@@ -60,10 +60,10 @@ public:
     void setFontName(String name) { m_fontName = name; }
 
     Color foregroundColor() const { return m_foregroundColor; }
-    void setForegroundColor(RGBA32 color) { m_foregroundColor.setRGB(color); }
+    void setForegroundColor(Color color) { m_foregroundColor = color; }
     
     Color backgroundColor() const { return m_backgroundColor; }
-    void setBackgroundColor(RGBA32 color) { m_backgroundColor.setRGB(color); }
+    void setBackgroundColor(Color color) { m_backgroundColor = color; }
 
     virtual void videoSizeDidChange(const IntSize&);