SVG objects with same idrefs conflict when under different shadow root

third_party/WebKit/Source/core/svg/SVGTreeScopeResources.h

Index: third_party/WebKit/Source/core/svg/SVGTreeScopeResources.h
diff --git a/third_party/WebKit/Source/core/svg/SVGTreeScopeResources.h b/third_party/WebKit/Source/core/svg/SVGTreeScopeResources.h
new file mode 100644
index 0000000000000000000000000000000000000000..376511a080c3af31048ed9bdcd7752b78f5b33bf
--- /dev/null
+++ b/third_party/WebKit/Source/core/svg/SVGTreeScopeResources.h
@@ -0,0 +1,55 @@
+// Copyright 2017 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.
+
+#ifndef SVGTreeScopeResources_h
+#define SVGTreeScopeResources_h
+
+#include "platform/heap/Handle.h"
+#include "wtf/Forward.h"
+#include "wtf/HashMap.h"
+#include "wtf/HashSet.h"
+#include "wtf/text/AtomicStringHash.h"
+
+namespace blink {
+
+class Element;
+class TreeScope;
+class LayoutSVGResourceContainer;
+
+class SVGTreeScopeResources

[pdr., 2017/01/23 04:34:12]

Can you add a very short comment here describing the class and why the resources
are on a treescope?

[fs, 2017/01/23 11:18:24]

Done.

+    : public GarbageCollectedFinalized<SVGTreeScopeResources> {
+  WTF_MAKE_NONCOPYABLE(SVGTreeScopeResources);
+
+ public:
+  typedef HeapHashSet<Member<Element>> SVGPendingElements;
+
+  explicit SVGTreeScopeResources(TreeScope*);
+  ~SVGTreeScopeResources();
+
+  void addResource(const AtomicString& id, LayoutSVGResourceContainer*);
+  void removeResource(const AtomicString& id);
+  LayoutSVGResourceContainer* resourceById(const AtomicString& id) const;
+
+  // Pending resources are such which are referenced by any object in the SVG
+  // document, but do NOT exist yet. For instance, dynamically built gradients
+  // / patterns / clippers...
+  void addPendingResource(const AtomicString& id, Element*);
+  bool hasPendingResource(const AtomicString& id) const;
+  bool isElementPendingResources(Element*) const;
+  bool isElementPendingResource(Element*, const AtomicString& id) const;
+  void clearHasPendingResourcesIfPossible(Element*);
+  void removeElementFromPendingResources(Element*);
+  SVGPendingElements* removePendingResource(const AtomicString& id);
+
+  DECLARE_TRACE();
+
+ private:
+  HashMap<AtomicString, LayoutSVGResourceContainer*> m_resources;
+  // Resources that are pending.
+  HeapHashMap<AtomicString, Member<SVGPendingElements>> m_pendingResources;
+};
+
+}  // namespace blink
+
+#endif  // SVGTreeScopeResources_h