Measure usage of createObjectURL and srcObject

third_party/WebKit/Source/core/fileapi/URLFileAPI.cpp

 // Copyright 2016 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 "core/fileapi/URLFileAPI.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "core/dom/DOMURL.h"
 #include "core/dom/ExecutionContext.h"
 #include "core/fileapi/Blob.h"
+#include "core/frame/UseCounter.h"
 #include "core/html/PublicURLManager.h"
 
 namespace blink {
 
 // static
 String URLFileAPI::createObjectURL(ExecutionContext* executionContext, Blob* blob, ExceptionState& exceptionState)
 {
     DCHECK(blob);
     DCHECK(executionContext);
 
     if (blob->isClosed()) {
+        // TODO(jsbell): The spec doesn't throw, but rather returns a blob: URL
+        // without adding it to the store.
         exceptionState.throwDOMException(InvalidStateError, String(blob->isFile() ? "File" : "Blob") + " has been closed.");
         return String();
     }
+
+    UseCounter::count(executionContext, UseCounter::CreateObjectURLBlob);
     return DOMURL::createPublicURL(executionContext, blob, blob->uuid());
 }
 
 // static
 void URLFileAPI::revokeObjectURL(ExecutionContext* executionContext, const String& urlString)
 {
     DCHECK(executionContext);
 
     KURL url(KURL(), urlString);
     executionContext->removeURLFromMemoryCache(url);
     executionContext->publicURLManager().revoke(url);
 }
 
 } // namespace blink