cc: Remove wtf includes from *LayerTextureUpdater headers

cc/scrollbar_layer.cc

Index: cc/scrollbar_layer.cc
diff --git a/cc/scrollbar_layer.cc b/cc/scrollbar_layer.cc
index 2aac77eabab0ac0aab39639ac5259a6f7280dede..38f33145c19fdf2561620f67c62723b6944e7c6b 100644
--- a/cc/scrollbar_layer.cc
+++ b/cc/scrollbar_layer.cc
@@ -177,10 +177,10 @@ private:
 void ScrollbarLayerChromium::setLayerTreeHost(CCLayerTreeHost* host)
 {
     if (!host || host != layerTreeHost()) {
-        m_backTrackUpdater.clear();
-        m_backTrack.clear();
-        m_thumbUpdater.clear();
-        m_thumb.clear();
+        m_backTrackUpdater = NULL;
+        m_backTrack.reset();
+        m_thumbUpdater = NULL;
+        m_thumb.reset();
     }
 
     LayerChromium::setLayerTreeHost(host);