Make `content` target build without unused data members on Linux.

content/renderer/websharedworker_proxy.h

Index: content/renderer/websharedworker_proxy.h
diff --git a/content/renderer/websharedworker_proxy.h b/content/renderer/websharedworker_proxy.h
index 276f956d2dad90ebb3164cc61b0be303086f477a..8ccc1f412d3d873f84b83037417b7fbcf21b51dd 100644
--- a/content/renderer/websharedworker_proxy.h
+++ b/content/renderer/websharedworker_proxy.h
@@ -64,22 +64,11 @@ class WebSharedWorkerProxy : public blink::WebSharedWorkerConnector,
   // routing ids).
   int route_id_;
 
-  // The routing id for the RenderFrame that created this worker.
-  int render_frame_route_id_;
-
   MessageRouter* const router_;
 
-  // ID of our parent document (used to shutdown workers when the parent
-  // document is detached).
-  unsigned long long document_id_;
-
   // Stores messages that were sent before the StartWorkerContext message.
   std::vector<IPC::Message*> queued_messages_;
 
-  // The id for the placeholder worker instance we've stored on the
-  // browser process (we need to pass this same route id back in when creating
-  // the worker).
-  int pending_route_id_;
   ConnectListener* connect_listener_;
   bool created_;