Web Audio: measure cross origin iframe usage.

third_party/WebKit/Source/modules/webaudio/AudioContext.cpp

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "modules/webaudio/AudioContext.h"
 
 #include "bindings/core/v8/ExceptionMessages.h"
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
 #include "core/dom/DOMException.h"
 #include "core/dom/ExceptionCode.h"
+#include "core/frame/UseCounter.h"
 #include "modules/webaudio/AudioBufferCallback.h"
 #include "platform/Histogram.h"
 #include "platform/audio/AudioUtilities.h"
 
 #if DEBUG_AUDIONODE_REFERENCES
 #include <stdio.h>
 #endif
 
 namespace blink {
 
 // Don't allow more than this number of simultaneous AudioContexts
 // talking to hardware.
 const unsigned MaxHardwareContexts = 6;
 static unsigned s_hardwareContextCount = 0;
 static unsigned s_contextId = 0;
 
 AbstractAudioContext* AudioContext::create(Document& document, ExceptionState& exceptionState)
 {
     ASSERT(isMainThread());
+
+    UseCounter::countCrossOriginIframe(document, UseCounter::AudioContextCrossOriginIframe);
+
     if (s_hardwareContextCount >= MaxHardwareContexts) {
         exceptionState.throwDOMException(
             NotSupportedError,
             ExceptionMessages::indexExceedsMaximumBound(
                 "number of hardware contexts",
                 s_hardwareContextCount,
                 MaxHardwareContexts));
         return nullptr;
     }
 
@@ skipping 160 matching lines @@
     ASSERT(destination());
 
     if (contextState() == Running) {
         destination()->audioDestinationHandler().stopRendering();
         setContextState(Suspended);
         deferredTaskHandler().clearHandlersToBeDeleted();
     }
 }
 
 } // namespace blink