Fix remaining cc files to compile with Clang

cc/ScrollbarLayerChromium.cpp

Index: cc/ScrollbarLayerChromium.cpp
diff --git a/cc/ScrollbarLayerChromium.cpp b/cc/ScrollbarLayerChromium.cpp
index 85801e6f2707449fb721e4e15d9ab60f83b64b35..80e36fb3522578d0a8d606615a139fe3a31eebda 100644
--- a/cc/ScrollbarLayerChromium.cpp
+++ b/cc/ScrollbarLayerChromium.cpp
@@ -38,6 +38,10 @@ ScrollbarLayerChromium::ScrollbarLayerChromium(PassOwnPtr<WebKit::WebScrollbar>
 {
 }
 
+ScrollbarLayerChromium::~ScrollbarLayerChromium()
+{
+}
+
 void ScrollbarLayerChromium::pushPropertiesTo(CCLayerImpl* layer)
 {
     LayerChromium::pushPropertiesTo(layer);
@@ -65,6 +69,11 @@ void ScrollbarLayerChromium::pushPropertiesTo(CCLayerImpl* layer)
         scrollbarLayer->setThumbResourceId(0);
 }
 
+ScrollbarLayerChromium* ScrollbarLayerChromium::toScrollbarLayerChromium()
+{
+    return this;
+}
+
 class ScrollbarBackgroundPainter : public LayerPainterChromium {
     WTF_MAKE_NONCOPYABLE(ScrollbarBackgroundPainter);
 public: