Update {virtual,override} to follow C++11 style in ppapi.

ppapi/host/ppapi_host.h

Index: ppapi/host/ppapi_host.h
diff --git a/ppapi/host/ppapi_host.h b/ppapi/host/ppapi_host.h
index 3f6e80dec7c1a48cef61154f5600e94257255f66..d4361dfeffd2019f36ec5911b498d2c9194eae86 100644
--- a/ppapi/host/ppapi_host.h
+++ b/ppapi/host/ppapi_host.h
@@ -46,15 +46,15 @@ class PPAPI_HOST_EXPORT PpapiHost : public IPC::Sender, public IPC::Listener {
   // (AddHostFactoryFilter) and instance messages (AddInstanceMessageFilter)
   // after construction.
   PpapiHost(IPC::Sender* sender, const PpapiPermissions& perms);
-  virtual ~PpapiHost();
+  ~PpapiHost() override;
 
   const PpapiPermissions& permissions() const { return permissions_; }
 
   // Sender implementation. Forwards to the sender_.
-  virtual bool Send(IPC::Message* msg) override;
+  bool Send(IPC::Message* msg) override;
 
   // Listener implementation.
-  virtual bool OnMessageReceived(const IPC::Message& msg) override;
+  bool OnMessageReceived(const IPC::Message& msg) override;
 
   // Sends the given reply message to the plugin.
   void SendReply(const ReplyMessageContext& context,