Remove Apple's unused implementation of private browsing from WebCore

Source/WebCore/page/Page.cpp

Index: Source/WebCore/page/Page.cpp
diff --git a/Source/WebCore/page/Page.cpp b/Source/WebCore/page/Page.cpp
index 908b43585b994286ed819bcfc9ed50a0e9e88478..51ebc57cfe32c4abd618dfa56516e9604ebcc254 100644
--- a/Source/WebCore/page/Page.cpp
+++ b/Source/WebCore/page/Page.cpp
@@ -987,22 +987,6 @@ void Page::storageBlockingStateChanged()
         pluginViewBases[i]->storageBlockingStateChanged();
 }
 
-void Page::privateBrowsingStateChanged()
-{
-    bool privateBrowsingEnabled = m_settings->privateBrowsingEnabled();
-
-    for (Frame* frame = mainFrame(); frame; frame = frame->tree()->traverseNext())
-        frame->document()->privateBrowsingStateDidChange();
-
-    // Collect the PluginViews in to a vector to ensure that action the plug-in takes
-    // from below privateBrowsingStateChanged does not affect their lifetime.
-    Vector<RefPtr<PluginViewBase>, 32> pluginViewBases;
-    collectPluginViews(pluginViewBases);
-
-    for (size_t i = 0; i < pluginViewBases.size(); ++i)
-        pluginViewBases[i]->privateBrowsingStateChanged(privateBrowsingEnabled);
-}
-
 #if !ASSERT_DISABLED
 void Page::checkSubframeCountConsistency() const
 {