Support UseCounter in dedicated workers.

Source/core/workers/DedicatedWorkerGlobalScope.cpp

Index: Source/core/workers/DedicatedWorkerGlobalScope.cpp
diff --git a/Source/core/workers/DedicatedWorkerGlobalScope.cpp b/Source/core/workers/DedicatedWorkerGlobalScope.cpp
index 357ca79f4e1cafceb28918280d18aed9bac204e2..c8c0bb038663e2c57620bb37e95557e6764e3075 100644
--- a/Source/core/workers/DedicatedWorkerGlobalScope.cpp
+++ b/Source/core/workers/DedicatedWorkerGlobalScope.cpp
@@ -78,11 +78,30 @@ void DedicatedWorkerGlobalScope::importScripts(const Vector<String>& urls, Excep
     thread()->workerObjectProxy().reportPendingActivity(hasPendingActivity());
 }
 
-DedicatedWorkerThread* DedicatedWorkerGlobalScope::thread()
+DedicatedWorkerThread* DedicatedWorkerGlobalScope::thread() const
 {
     return static_cast<DedicatedWorkerThread*>(Base::thread());
 }
 
+class UseCounterTask : public ExecutionContextTask {
+public:
+    static PassOwnPtr<UseCounterTask> create(UseCounter::Feature feature) { return adoptPtr(new UseCounterTask(feature)); }
+
+private:
+    explicit UseCounterTask(UseCounter::Feature feature) : m_feature(feature) { }
+    virtual void performTask(ExecutionContext* context) OVERRIDE
+    {
+        UseCounter::count(*toDocument(context), m_feature);
+    }
+
+    UseCounter::Feature m_feature;
+};
+
+void DedicatedWorkerGlobalScope::countFeature(UseCounter::Feature feature) const
+{
+    thread()->workerObjectProxy().postTaskToMainExecutionContext(UseCounterTask::create(feature));
+}
+
 void DedicatedWorkerGlobalScope::trace(Visitor* visitor)
 {
     WorkerGlobalScope::trace(visitor);