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 54881b1d527f87c67ca1461935e292a2decccbb5..7888a528174f7ee36a6d9678fffbe4d472eba0fb 100644
--- a/Source/core/frame/LocalDOMWindow.cpp
+++ b/Source/core/frame/LocalDOMWindow.cpp
@@ -311,16 +311,6 @@ void LocalDOMWindow::clearDocument()
     if (!m_document)
         return;
 
-    if (m_document->isActive()) {

[dcheng, 2015/04/03 14:35:45]

I moved this directly into the XSLT code so we don't need to special-case it
here.

I should add an assert that the document is inactive though (I'll do that in a
followup patch set).

-        // 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();