Track connected subframes per-Document instead of per-Node.

third_party/WebKit/Source/core/dom/SubframeTracker.cpp

Index: third_party/WebKit/Source/core/dom/SubframeTracker.cpp
diff --git a/third_party/WebKit/Source/core/dom/SubframeTracker.cpp b/third_party/WebKit/Source/core/dom/SubframeTracker.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..f661676f82255de0c1daf1dfde44fcba75e66e1d
--- /dev/null
+++ b/third_party/WebKit/Source/core/dom/SubframeTracker.cpp
@@ -0,0 +1,92 @@
+// Copyright 2016 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 "core/dom/SubframeTracker.h"
+
+#include "core/dom/Node.h"
+#include "core/html/HTMLFrameOwnerElement.h"
+
+namespace blink {
+
+SubframeTracker::SubframeTracker() = default;
+
+bool SubframeTracker::hasConnectedSubframes(Node& node) const
+{
+    return m_connectedSubframeNodes.contains(&node);
+}
+
+void SubframeTracker::disconnectSubframesAt(Node& root, DisconnectPolicy policy)
+{
+    auto it = m_connectedSubframeNodes.find(&root);
+    if (it == m_connectedSubframeNodes.end())
+        return;
+
+    if (policy == DescendantsOnly)
+        ++it;
+
+    WillBeHeapVector<RefPtrWillBeMember<HTMLFrameOwnerElement>, 10> frameOwners;
+    for (; it != m_connectedSubframeNodes.end() && root.containsIncludingShadowDOM(*it); ++it) {
+        if ((*it)->isFrameOwnerElement())
+            frameOwners.append(toHTMLFrameOwnerElement(*it));
+    }
+
+    for (size_t i = 0; i < frameOwners.size(); ++i) {
+        HTMLFrameOwnerElement* owner = frameOwners[i].get();
+        // Don't need to traverse up the tree for the first owner since no
+        // script could have moved it.
+        if (!i || root.containsIncludingShadowDOM(owner))
+            owner->disconnectContentFrame();
+    }
+}
+
+DEFINE_TRACE(SubframeTracker)
+{
+#if ENABLE(OILPAN)
+    visitor->trace(m_connectedSubframeNodes);
+#endif // ENABLE(OILPAN)
+}
+
+void SubframeTracker::connectSubframe(HTMLFrameOwnerElement& owner)
+{
+    WillBeHeapVector<RawPtrWillBeMember<Node>> pathToOwner;
+    for (ContainerNode* node = &owner; node; node = node->parentOrShadowHostNode())
+        pathToOwner.append(node);
+
+    // Find the lowest node in the ancestor chain that's not already tracked in
+    // the set of connected subframe nodes.
+    SubframeNodeSet::iterator insertionLocation = m_connectedSubframeNodes.end();
+    auto node = pathToOwner.rbegin();
+    for (; node != pathToOwner.rend(); ++node) {
+        auto it = m_connectedSubframeNodes.find(*node);
+        if (it == m_connectedSubframeNodes.end())
+            break;
+        insertionLocation = it;
+    }
+
+    // Insert the remainder of the chain immediately after the last found node.
+    if (insertionLocation != m_connectedSubframeNodes.end()) {
+        // LinkedHashSet only exposes insertBefore(), so increment the iterator.
+        ++insertionLocation;
+    }
+
+    for (; node != pathToOwner.rend(); ++node)
+        m_connectedSubframeNodes.insertBefore(insertionLocation, *node);
+}
+
+void SubframeTracker::disconnectSubframe(HTMLFrameOwnerElement& owner)
+{
+    for (ContainerNode* node = &owner; node; node = node->parentOrShadowHostNode()) {
+        ASSERT(!m_connectedSubframeNodes.isEmpty());
+        auto it = m_connectedSubframeNodes.find(node);
+        ASSERT(it != m_connectedSubframeNodes.end());
+        auto nextNode = it;
+        // If the next node in |m_connectedSubframeNodes| is a child of this
+        // node, it can't be removed since there are still connected subframes.
+        if (*nextNode != m_connectedSubframeNodes.last() && (*++nextNode)->parentOrShadowHostNode() == node)
+            return;
+        m_connectedSubframeNodes.remove(it);
+    }
+}
+
+} // namespace blink