Fix CC*Renderer and CC*LayerImpl to compile with Clang

cc/CCIOSurfaceLayerImpl.cpp

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 
 #if USE(ACCELERATED_COMPOSITING)
 
 #include "CCIOSurfaceLayerImpl.h"
 
@@ skipping 89 matching lines @@
 }
 
 void CCIOSurfaceLayerImpl::setIOSurfaceProperties(unsigned ioSurfaceId, const IntSize& size)
 {
     if (m_ioSurfaceId != ioSurfaceId)
         m_ioSurfaceChanged = true;
 
     m_ioSurfaceId = ioSurfaceId;
     m_ioSurfaceSize = size;
 }
+
+const char* CCIOSurfaceLayerImpl::layerTypeAsString() const
+{
+    return "IOSurfaceLayer";
+}
+
 }
 
 #endif // USE(ACCELERATED_COMPOSITING)