Add Worker support for FileSystem API.

chrome/worker/webworker_stub.h

Index: chrome/worker/webworker_stub.h
diff --git a/chrome/worker/webworker_stub.h b/chrome/worker/webworker_stub.h
index 473158861fc3b1c6858626a03d817e47c804e46c..584abce4bf552f8cec4ffc15377ffd573abb8546 100644
--- a/chrome/worker/webworker_stub.h
+++ b/chrome/worker/webworker_stub.h
@@ -25,6 +25,8 @@ class WebWorkerStub : public WebWorkerStubBase {
   virtual void OnMessageReceived(const IPC::Message& message);
   virtual void OnChannelError();
 
+  virtual const GURL& url() const { return url_; }
+
  private:
   virtual ~WebWorkerStub();
 
@@ -34,6 +36,7 @@ class WebWorkerStub : public WebWorkerStubBase {
                      const std::vector<int>& new_routing_ids);
 
   WebKit::WebWorker* impl_;
+  GURL url_;
 
   DISALLOW_COPY_AND_ASSIGN(WebWorkerStub);
 };