Bug 1532354 - Remove unused DeleteGMPServiceParent class. r=cpearce

Bug 1352924 removed the usage of this class, so we can safely remove the dead
code.

Differential Revision: https://phabricator.services.mozilla.com/D21968

--HG--
extra : moz-landing-system : lando

dom/media/gmp/GMPServiceParent.cpp

@@ -1729,17 +1729,6 @@ mozilla::ipc::IPCResult GMPServiceParent::RecvGetGMPNodeId(
   return IPC_OK();
 }
 
-class DeleteGMPServiceParent : public mozilla::Runnable {
- public:
-  explicit DeleteGMPServiceParent(GMPServiceParent* aToDelete)
-      : Runnable("gmp::DeleteGMPServiceParent"), mToDelete(aToDelete) {}
-
-  NS_IMETHOD Run() override { return NS_OK; }
-
- private:
-  nsAutoPtr<GMPServiceParent> mToDelete;
-};
-
 void GMPServiceParent::CloseTransport(Monitor* aSyncMonitor, bool* aCompleted) {
   MOZ_ASSERT(MessageLoop::current() == XRE_GetIOMessageLoop());