Use ChildFrameDisconnector when detaching child frames of a LocalFrame.

third_party/WebKit/Source/core/frame/LocalFrame.cpp

Index: third_party/WebKit/Source/core/frame/LocalFrame.cpp
diff --git a/third_party/WebKit/Source/core/frame/LocalFrame.cpp b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
index 5477e36ce1ea3d8a125d719ce31674013aed88ad..b6947d2ca8fbb527ea8f5c87e1a42bfe68082b04 100644
--- a/third_party/WebKit/Source/core/frame/LocalFrame.cpp
+++ b/third_party/WebKit/Source/core/frame/LocalFrame.cpp
@@ -31,6 +31,7 @@
 
 #include "bindings/core/v8/ScriptController.h"
 #include "core/InstrumentingAgents.h"
+#include "core/dom/ChildFrameDisconnector.h"
 #include "core/dom/DocumentType.h"
 #include "core/dom/StyleChangeReason.h"
 #include "core/editing/EditingUtilities.h"
@@ -447,6 +448,14 @@ bool LocalFrame::shouldClose()
     return m_loader.shouldClose();
 }
 
+void LocalFrame::detachChildren()
+{
+    DCHECK(m_loader.stateMachine()->creatingInitialEmptyDocument() || document());
+
+    if (document())

[esprehn, 2016/07/13 02:35:45]

if (Document* document = this->document())

avoids the nested virtual calls down there.

[dcheng, 2016/07/13 02:51:34]

Done.

+        ChildFrameDisconnector(*document()).disconnect();
+}
+
 void LocalFrame::willDetachFrameHost()
 {
     LocalFrameLifecycleNotifier::notifyWillDetachFrameHost();