Put QUICHE_EXPORT on IndeterminateLengthDecoder

For Chrome win build.

PiperOrigin-RevId: 779008605
diff --git a/quiche/binary_http/binary_http_message.h b/quiche/binary_http/binary_http_message.h
index 85fb1dd..0a28e0a 100644
--- a/quiche/binary_http/binary_http_message.h
+++ b/quiche/binary_http/binary_http_message.h
@@ -176,7 +176,7 @@
   // Provides a Decode method that can be called multiple times as data is
   // received. The relevant MessageSectionHandler method will be called when
   // its corresponding section is successfully decoded.
-  class IndeterminateLengthDecoder {
+  class QUICHE_EXPORT IndeterminateLengthDecoder {
    public:
     // The handler to invoke when a section is decoded successfully.
     class MessageSectionHandler {