Revert of Refactor frame navigation/detach state cleanup to be more sane.

Source/core/frame/LocalDOMWindow.cpp

Index: Source/core/frame/LocalDOMWindow.cpp
diff --git a/Source/core/frame/LocalDOMWindow.cpp b/Source/core/frame/LocalDOMWindow.cpp
index 0c636c0bd315c613ab58748e3a472d3563458a3d..54881b1d527f87c67ca1461935e292a2decccbb5 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -311,7 +311,15 @@
     if (!m_document)
         return;
 
-    ASSERT(!m_document->isActive());
+    if (m_document->isActive()) {
+        // FIXME: We don't call willRemove here. Why is that OK?
+        // This detach() call is also mostly redundant. Most of the calls to
+        // this function come via DocumentLoader::createWriterFor, which
+        // always detaches the previous Document first. Only XSLTProcessor
+        // depends on this detach() call, so it seems like there's some room
+        // for cleanup.
+        m_document->detach();
+    }
 
     // FIXME: This should be part of ActiveDOMObject shutdown
     clearEventQueue();