Fix remaining cc files to compile with Clang

cc/ScrollbarLayerChromium.h

Index: cc/ScrollbarLayerChromium.h
diff --git a/cc/ScrollbarLayerChromium.h b/cc/ScrollbarLayerChromium.h
index b4b8b8bc6298e53263b64a5d78a14dd2fe28687d..62ace2d20e1cad884e82daedc2dd678311636235 100644
--- a/cc/ScrollbarLayerChromium.h
+++ b/cc/ScrollbarLayerChromium.h
@@ -23,8 +23,11 @@ class CCTextureUpdateQueue;
 class ScrollbarLayerChromium : public LayerChromium {
 public:
     virtual PassOwnPtr<CCLayerImpl> createCCLayerImpl() OVERRIDE;
+
     static PassRefPtr<ScrollbarLayerChromium> create(PassOwnPtr<WebKit::WebScrollbar>, WebKit::WebScrollbarThemePainter, PassOwnPtr<WebKit::WebScrollbarThemeGeometry>, int scrollLayerId);
 
+    virtual ~ScrollbarLayerChromium();
+
     // LayerChromium interface
     virtual void setTexturePriorities(const CCPriorityCalculator&) OVERRIDE;
     virtual void update(CCTextureUpdateQueue&, const CCOcclusionTracker*, CCRenderingStats&) OVERRIDE;
@@ -34,7 +37,7 @@ public:
     int scrollLayerId() const { return m_scrollLayerId; }
     void setScrollLayerId(int id) { m_scrollLayerId = id; }
 
-    virtual ScrollbarLayerChromium* toScrollbarLayerChromium() OVERRIDE { return this; }
+    virtual ScrollbarLayerChromium* toScrollbarLayerChromium() OVERRIDE;
 
 protected:
     ScrollbarLayerChromium(PassOwnPtr<WebKit::WebScrollbar>, WebKit::WebScrollbarThemePainter, PassOwnPtr<WebKit::WebScrollbarThemeGeometry>, int scrollLayerId);