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

Source/core/page/Frame.cpp

Index: Source/core/page/Frame.cpp
diff --git a/Source/core/page/Frame.cpp b/Source/core/page/Frame.cpp
index 9d0536fea510285e07788be1e71882e5df61d010..3f231af9bc0a503d417e3cff82fb70a17782ed3a 100644
--- a/Source/core/page/Frame.cpp
+++ b/Source/core/page/Frame.cpp
@@ -459,7 +459,7 @@ PassRefPtr<Range> Frame::rangeForPoint(const IntPoint& framePoint)
     return 0;
 }
 
-void Frame::createView(const IntSize& viewportSize, const StyleColor& backgroundColor, bool transparent,
+void Frame::createView(const IntSize& viewportSize, const Color& backgroundColor, bool transparent,
     const IntSize& fixedLayoutSize, bool useFixedLayout, ScrollbarMode horizontalScrollbarMode, bool horizontalLock,
     ScrollbarMode verticalScrollbarMode, bool verticalLock)
 {
@@ -486,7 +486,7 @@ void Frame::createView(const IntSize& viewportSize, const StyleColor& background
     setView(frameView);
 
     if (backgroundColor.isValid())
-        frameView->updateBackgroundRecursively(backgroundColor.color(), transparent);
+        frameView->updateBackgroundRecursively(backgroundColor, transparent);
 
     if (isMainFrame)
         frameView->setParentVisible(true);