Simplify setting lockBackForwardList() in NavigationScheduler.

Source/core/loader/HistoryController.cpp

Index: Source/core/loader/HistoryController.cpp
diff --git a/Source/core/loader/HistoryController.cpp b/Source/core/loader/HistoryController.cpp
index 355156f0bac6bdfd9abad0bc134c8ddbfbeddfdf..8f357482da7f0d3912a5c10ca646f6bbfc8fe96c 100644
--- a/Source/core/loader/HistoryController.cpp
+++ b/Source/core/loader/HistoryController.cpp
@@ -376,17 +376,6 @@ HistoryItem* HistoryController::currentItem(Frame* frame) const
     return m_currentEntry ? m_currentEntry->itemForFrame(frame) : 0;
 }
 
-bool HistoryController::currentItemShouldBeReplaced(Frame* frame) const
-{
-    // From the HTML5 spec for location.assign():
-    //  "If the browsing context's session history contains only one Document,
-    //   and that was the about:blank Document created when the browsing context
-    //   was created, then the navigation must be done with replacement enabled."
-    if (m_previousEntry && m_previousEntry->itemForFrame(frame))
-        return false;
-    return equalIgnoringCase(frame->document()->url(), blankURL());
-}
-
 HistoryItem* HistoryController::previousItem(Frame* frame) const
 {
     return m_previousEntry ? m_previousEntry->itemForFrame(frame) : 0;