Support performance.now() in workers.

Source/modules/performance/WorkerContextPerformance.h

Index: Source/modules/performance/WorkerContextPerformance.h
diff --git a/Source/modules/donottrack/NavigatorDoNotTrack.h b/Source/modules/performance/WorkerContextPerformance.h
similarity index 75%
copy from Source/modules/donottrack/NavigatorDoNotTrack.h
copy to Source/modules/performance/WorkerContextPerformance.h
index 0c044e7cd8edef2f8860c374d59f077e1e963816..af56e15a9af37ef53515dc07fd698c7463d97b9b 100644
--- a/Source/modules/donottrack/NavigatorDoNotTrack.h
+++ b/Source/modules/performance/WorkerContextPerformance.h
@@ -28,32 +28,32 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#ifndef NavigatorDoNotTrack_h
-#define NavigatorDoNotTrack_h
+#ifndef WorkerContextPerformance_h
+#define WorkerContextPerformance_h
 
-#include "core/page/DOMWindowProperty.h"
 #include "core/platform/Supplementable.h"
-#include "wtf/text/WTFString.h"
 
 namespace WebCore {
 
-class Frame;
-class Navigator;
+class ScriptExecutionContext;
+class WorkerPerformance;
 
-class NavigatorDoNotTrack : public Supplement<Navigator>, public DOMWindowProperty {
+class WorkerContextPerformance : public Supplement<ScriptExecutionContext> {
 public:
-    virtual ~NavigatorDoNotTrack();
-    static NavigatorDoNotTrack* from(Navigator*);
+    virtual ~WorkerContextPerformance();
+    static WorkerContextPerformance* from(ScriptExecutionContext*);
 
-    static String doNotTrack(Navigator*);
-
-    String doNotTrack();
+    static WorkerPerformance* performance(ScriptExecutionContext*);
 
 private:
-    explicit NavigatorDoNotTrack(Frame*);
+    WorkerContextPerformance();
+
+    WorkerPerformance* getPerformance(ScriptExecutionContext*);
     static const char* supplementName();
+
+    RefPtr<WorkerPerformance> m_performance;
 };
 
 } // namespace WebCore
 
-#endif // NavigatorDoNotTrack_h
+#endif // WorkerContextPerformance_h