Update third_party/protobuf to protobuf-v3.0.0-beta-3

third_party/protobuf/src/google/protobuf/arena.h

Index: third_party/protobuf/src/google/protobuf/arena.h
diff --git a/third_party/protobuf/src/google/protobuf/arena.h b/third_party/protobuf/src/google/protobuf/arena.h
index 6a35183ebacb9b0de6788a07fdb42523f02fc10a..cf07b9fc97c0cf4b7f7f4dba9caa5a9edc963833 100644
--- a/third_party/protobuf/src/google/protobuf/arena.h
+++ b/third_party/protobuf/src/google/protobuf/arena.h
@@ -56,6 +56,7 @@ using type_info = ::type_info;
 #include <google/protobuf/stubs/mutex.h>
 #include <google/protobuf/stubs/type_traits.h>
 
+
 namespace google {
 namespace protobuf {
 
@@ -76,7 +77,7 @@ template<typename T> void arena_destruct_object(void* object) {
 template<typename T> void arena_delete_object(void* object) {
   delete reinterpret_cast<T*>(object);
 }
-inline void arena_free(void* object, size_t size) {
+inline void arena_free(void* object, size_t /* size */) {
   free(object);
 }
 
@@ -210,7 +211,12 @@ struct ArenaOptions {
 //
 // This protocol is implemented by all arena-enabled proto2 message classes as
 // well as RepeatedPtrField.
+
+#if __cplusplus >= 201103L
+class LIBPROTOBUF_EXPORT Arena final {
+#else
 class LIBPROTOBUF_EXPORT Arena {
+#endif
  public:
   // Arena constructor taking custom options. See ArenaOptions below for
   // descriptions of the options available.
@@ -446,6 +452,10 @@ class LIBPROTOBUF_EXPORT Arena {
   // As above, but does not include any free space in underlying blocks.
   GOOGLE_ATTRIBUTE_NOINLINE uint64 SpaceUsed() const;
 
+  // Combines SpaceAllocated and SpaceUsed. Returns a pair of
+  // <space_allocated, space_used>.
+  GOOGLE_ATTRIBUTE_NOINLINE pair<uint64, uint64> SpaceAllocatedAndUsed() const;
+
   // Frees all storage allocated by this arena after calling destructors
   // registered with OwnDestructor() and freeing objects registered with Own().
   // Any objects allocated on this arena are unusable after this call. It also
@@ -507,11 +517,11 @@ class LIBPROTOBUF_EXPORT Arena {
   //
   // This is inside Arena because only Arena has the friend relationships
   // necessary to see the underlying generated code traits.
-  template<typename T>
-  struct is_arena_constructable :
-      public google::protobuf::internal::integral_constant<bool,
-          sizeof(InternalIsArenaConstructableHelper::ArenaConstructable<
-                 const T>(static_cast<const T*>(0))) == sizeof(char)> {
+  template <typename T>
+  struct is_arena_constructable
+      : public google::protobuf::internal::integral_constant<
+            bool, sizeof(InternalIsArenaConstructableHelper::ArenaConstructable<
+                         const T>(static_cast<const T*>(0))) == sizeof(char)> {
   };
 
  private: