Expose performance.memory in workers

public/web/WebSharedWorker.h

Index: public/web/WebSharedWorker.h
diff --git a/public/web/WebSharedWorker.h b/public/web/WebSharedWorker.h
index 27365ad89b228a90cf42564ac276dee867caf0f2..34afaea7e81aee8953c571403d0b850cc085c2fc 100644
--- a/public/web/WebSharedWorker.h
+++ b/public/web/WebSharedWorker.h
@@ -44,6 +44,7 @@ class WebString;
 class WebMessagePortChannel;
 class WebSharedWorkerClient;
 class WebURL;
+class WebWorkerSettings;
 
 // This is the interface to a SharedWorker thread.
 class WebSharedWorker {
@@ -72,6 +73,8 @@ public:
     virtual void reattachDevTools(const WebString& savedState) = 0;
     virtual void detachDevTools() = 0;
     virtual void dispatchDevToolsMessage(const WebString&) = 0;
+
+    virtual WebWorkerSettings* settings() = 0;
 };
 
 } // namespace blink