Warn developers about deprecated features only once per page-load.

Source/core/page/PageConsole.cpp

 /*
  * Copyright (C) 2013 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 36 matching lines @@
 #include <stdio.h>
 #include <wtf/UnusedParam.h>
 #include <wtf/text/CString.h>
 #include <wtf/text/WTFString.h>
 
 #include "TraceEvent.h"
 
 namespace WebCore {
 
 namespace {
-    int muteCount = 0;
+
+int muteCount = 0;
+
+// Ensure that this stays in sync with the DeprecatedFeature enum.
+static const char* const deprecationMessages[] = {
+    "The 'X-WebKit-CSP' headers are deprecated; please consider using the canonical 'Content-Security-Policy' header instead."
+};
+
+COMPILE_ASSERT(WTF_ARRAY_LENGTH(deprecationMessages) == static_cast<int>(WebCore::PageConsole::NumberOfFeatures), DeprecationMessages_matches_enum);
+
 }
 
-PageConsole::PageConsole(Page* page) : m_page(page) { }
+PageConsole::PageConsole(Page* page)
+    : m_page(page)
+    , m_deprecationNotifications(NumberOfFeatures)
+{
+}
 
 PageConsole::~PageConsole() { }
 
 void PageConsole::addMessage(MessageSource source, MessageLevel level, const String& message, unsigned long requestIdentifier, Document* document)
 {
     String url;
     if (document)
         url = document->url().string();
     unsigned line = 0;
     if (document && document->parsing() && !document->isInDocumentWrite() && document->scriptableDocumentParser()) {
@@ skipping 35 matching lines @@
     muteCount++;
 }
 
 // static
 void PageConsole::unmute()
 {
     ASSERT(muteCount > 0);
     muteCount--;
 }
 
+// static
+void PageConsole::reportDeprecation(Document* document, DeprecatedFeature feature)
+{
+    if (!document)
+        return;
+
+    Page* page = document->page();
+    if (!page || !page->console())
+        return;
+
+    page->console()->addDeprecationMessage(feature);
+}
+
+void PageConsole::addDeprecationMessage(DeprecatedFeature feature)
+{
+    ASSERT(feature < NumberOfFeatures);
+
+    if (m_deprecationNotifications.quickGet(feature))
+        return;
+
+    m_deprecationNotifications.quickSet(feature);
+    addMessage(DeprecationMessageSource, WarningMessageLevel, ASCIILiteral(deprecationMessages[feature]));
+}
+
 } // namespace WebCore