C++ Bindings: Remove 'inline' arg from generated union serialization functions.

mojo/public/cpp/bindings/lib/map_serialization.h

Index: mojo/public/cpp/bindings/lib/map_serialization.h
diff --git a/mojo/public/cpp/bindings/lib/map_serialization.h b/mojo/public/cpp/bindings/lib/map_serialization.h
index d691cf88fbdb1d50f59fe12a6507c40e2f8f7b63..8605cb75c9c1ae6ffb3e29d083bc6d08cdbf0881 100644
--- a/mojo/public/cpp/bindings/lib/map_serialization.h
+++ b/mojo/public/cpp/bindings/lib/map_serialization.h
@@ -75,11 +75,11 @@ struct MapSerializer<
 template <typename U, typename U_Data>
 struct MapSerializer<U, U_Data, true, true> {
   static size_t GetBaseArraySize(size_t count) {
-    return count * sizeof(U_Data);
-  }
-  static size_t GetItemSize(const U& item) {
-    return GetSerializedSize_(item, true);
+    // GetSerializedSize_ (called in GetItemSize()) will account for
+    // sizeof(U_Data), so prevent double counting by having this count be 0.
+    return 0;
   }
+  static size_t GetItemSize(const U& item) { return GetSerializedSize_(item); }
 };
 
 template <>