Add support for SVG Clip paths in HTML

Source/core/rendering/RenderLayerClipPathInfo.cpp

Index: Source/core/rendering/RenderLayerClipPathInfo.cpp
diff --git a/Source/core/rendering/RenderLayerClipPathInfo.cpp b/Source/core/rendering/RenderLayerClipPathInfo.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..ecb1ed87087bc57fd54de68266c41ebe70e244e3
--- /dev/null
+++ b/Source/core/rendering/RenderLayerClipPathInfo.cpp
@@ -0,0 +1,54 @@
+// Copyright 2014 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"
+
+#include "core/rendering/RenderLayerClipPathInfo.h"
+
+#include "core/rendering/RenderLayer.h"
+#include "core/rendering/svg/RenderSVGResourceContainer.h"
+
+namespace blink {
+
+RenderLayerClipPathInfo::RenderLayerClipPathInfo(RenderLayer* layer)
+    : m_layer(layer)
+{
+}
+
+RenderLayerClipPathInfo::~RenderLayerClipPathInfo()
+{
+    removeReferenceClipPathClients();
+}
+
+void RenderLayerClipPathInfo::updateReferenceClipPathClients(ClipPathOperation* clipPathOperation)
+{
+    ASSERT(clipPathOperation->type() == ClipPathOperation::REFERENCE);
+
+    removeReferenceClipPathClients();
+    ReferenceClipPathOperation* referenceClipPathOperation = toReferenceClipPathOperation(clipPathOperation);
+    Element* clipPath = m_layer->renderer()->node()->document().getElementById(referenceClipPathOperation->fragment());
+    if (!isSVGClipPathElement(clipPath))
+        return;
+    if (clipPath->renderer())
+        toRenderSVGResourceContainer(clipPath->renderer())->addClientRenderLayer(m_layer);
+    else
+        toSVGClipPathElement(clipPath)->addClient(m_layer->renderer()->node());
+
+    m_clipPathElement = PassRefPtr<SVGClipPathElement>(toSVGClipPathElement(clipPath));
+}
+
+void RenderLayerClipPathInfo::removeReferenceClipPathClients()
+{
+    if (!m_clipPathElement)
+        return;
+
+    if (m_clipPathElement->renderer())
+        toRenderSVGResourceContainer(m_clipPathElement->renderer())->removeClientRenderLayer(m_layer);
+    else
+        m_clipPathElement->removeClient(m_layer->renderer()->node());
+
+    m_clipPathElement.clear();
+}
+
+} // namespace blink