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

Source/core/page/DeprecationAgent.cpp

 /*
- * Copyright (C) 2012 Google, Inc. All rights reserved.
+ * Copyright (C) 2013 Google, 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
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY GOOGLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #include "config.h"
-#include "UseCounter.h"
+#include "DeprecationAgent.h"
 
-#include "DOMWindow.h"
 #include "Document.h"
-#include "HistogramSupport.h"
 #include "Page.h"
+#include "PageConsole.h"
+#include <wtf/BitVector.h>
+#include <wtf/Noncopyable.h>
+#include <wtf/OwnPtr.h>
+#include <wtf/PassOwnPtr.h>
+#include <wtf/text/WTFString.h>
 
 namespace WebCore {
 
-UseCounter::UseCounter()
+namespace {
+
+// Ensure that this stays in sync with the Feature 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::DeprecationAgent::NumberOfFeatures), DeprecationMessages_matches_Feature_enum);

[pfeldman, 2013/04/19 13:04:22]

It should work, right?

+
+}
+
+DeprecationAgent::DeprecationAgent()
 {
 }
 
-UseCounter::~UseCounter()
+DeprecationAgent::~DeprecationAgent()
 {
-    // We always log PageDestruction so that we have a scale for the rest of the features.
-    HistogramSupport::histogramEnumeration("WebCore.FeatureObserver", PageDestruction, NumberOfFeatures);
-
-    updateMeasurements();
 }
 
-void UseCounter::updateMeasurements()
-{
-    HistogramSupport::histogramEnumeration("WebCore.FeatureObserver", PageVisits, NumberOfFeatures);
-
-    if (!m_countBits)
-        return;
-
-    for (unsigned i = 0; i < NumberOfFeatures; ++i) {
-        if (m_countBits->quickGet(i))
-            HistogramSupport::histogramEnumeration("WebCore.FeatureObserver", i, NumberOfFeatures);
-    }
-
-    // Clearing count bits is timing sensitive.
-    m_countBits->clearAll();
-}
-
-void UseCounter::didCommitLoad()
-{
-    updateMeasurements();
-}
-
-void UseCounter::observe(Document* document, Feature feature)
+void DeprecationAgent::notify(Document* document, Feature feature)
 {
     if (!document)
         return;
 
     Page* page = document->page();
     if (!page)
         return;
 
-    page->useCounter()->didObserve(feature);
+    page->deprecationAgent()->sendNotification(page->console(), feature);
 }
 
-void UseCounter::observe(DOMWindow* domWindow, Feature feature)
+void DeprecationAgent::sendNotification(PageConsole* console, Feature feature)
 {
-    ASSERT(domWindow);
-    observe(domWindow->document(), feature);
+    ASSERT(feature < NumberOfFeatures);
+    ASSERT(console);
+
+    if (!m_countBits) {
+        m_countBits = adoptPtr(new BitVector(NumberOfFeatures));
+        m_countBits->clearAll();
+    }
+
+    if (m_countBits->quickGet(feature))

[pfeldman, 2013/04/19 13:04:22]

Is this covered with the tests? I.e. are you generating a number of them and
check that notification only comes once?

+        return;
+
+    m_countBits->quickSet(feature);
+    console->addMessage(DeprecationMessageSource, WarningMessageLevel, ASCIILiteral(deprecationMessages[feature]));
 }
 
 } // namespace WebCore