Merge pull request #4695 from bogdandrutu/master

Add a virtual destructor for the ClientContext::GlobalCallbacks.

include/grpc++/client_context.h

@@ -286,6 +286,7 @@ class ClientContext {
   /// a client context is constructed and destructed.
   class GlobalCallbacks {
    public:
+    virtual ~GlobalCallbacks() {}
     virtual void DefaultConstructor(ClientContext* context) = 0;
     virtual void Destructor(ClientContext* context) = 0;
   };

src/cpp/client/client_context.cc

 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -48,6 +48,7 @@ namespace grpc {
 class DefaultGlobalClientCallbacks GRPC_FINAL
     : public ClientContext::GlobalCallbacks {
  public:
+  ~DefaultGlobalClientCallbacks() GRPC_OVERRIDE {}
   void DefaultConstructor(ClientContext* context) GRPC_OVERRIDE {}
   void Destructor(ClientContext* context) GRPC_OVERRIDE {}
 };

src/cpp/server/server.cc

 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,6 +53,7 @@ namespace grpc {
 
 class DefaultGlobalCallbacks GRPC_FINAL : public Server::GlobalCallbacks {
  public:
+  ~DefaultGlobalCallbacks() GRPC_OVERRIDE {}
   void PreSynchronousRequest(ServerContext* context) GRPC_OVERRIDE {}
   void PostSynchronousRequest(ServerContext* context) GRPC_OVERRIDE {}
 };