[HTMLImport] Add an Usecounter if imported ducmnet has stylesheets.

Source/core/html/imports/HTMLImportChild.cpp

 /*
  * 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 13 matching lines @@
  * 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 "core/html/imports/HTMLImportChild.h"
 
+#include "core/css/StyleSheetList.h"
 #include "core/dom/Document.h"
 #include "core/dom/custom/CustomElement.h"
 #include "core/dom/custom/CustomElementMicrotaskImportStep.h"
 #include "core/dom/custom/CustomElementSyncMicrotaskQueue.h"
+#include "core/frame/UseCounter.h"
 #include "core/html/imports/HTMLImportChildClient.h"
 #include "core/html/imports/HTMLImportLoader.h"
 #include "core/html/imports/HTMLImportTreeRoot.h"
 #include "core/html/imports/HTMLImportsController.h"
 
 namespace blink {
 
 HTMLImportChild::HTMLImportChild(const KURL& url, HTMLImportLoader* loader, SyncMode sync)
     : HTMLImport(sync)
     , m_url(url)
@@ skipping 33 matching lines @@
 
 void HTMLImportChild::didFinish()
 {
     if (m_client)
         m_client->didFinish();
 }
 
 void HTMLImportChild::didFinishLoading()
 {
     stateWillChange();
+    if (document() && document()->styleSheets()->length() > 0)
+        UseCounter::count(root()->document(), UseCounter::HTMLImportsHasStyleSheets);
     CustomElement::didFinishLoadingImport(*(root()->document()));
 }
 
 void HTMLImportChild::didFinishUpgradingCustomElements()
 {
     stateWillChange();
     m_customElementMicrotaskStep.clear();
 }
 
 void HTMLImportChild::dispose()
@@ skipping 122 matching lines @@
 
 DEFINE_TRACE(HTMLImportChild)
 {
     visitor->trace(m_customElementMicrotaskStep);
     visitor->trace(m_loader);
     visitor->trace(m_client);
     HTMLImport::trace(visitor);
 }
 
 } // namespace blink