Add QUICHE_EXPORT to the public inner class in binary_http_message.h

Some of the methods of these inner classes were causing linking errors on Chrome Windows builds. See https://ci.chromium.org/ui/p/chromium/builders/try/win_chromium_compile_dbg_ng/1338006/overview for reference.

PiperOrigin-RevId: 485419068

quiche/binary_http/binary_http_message.h

diff --git a/quiche/binary_http/binary_http_message.h b/quiche/binary_http/binary_http_message.h
index 91d5b1c..70b8106 100644
--- a/quiche/binary_http/binary_http_message.h
+++ b/quiche/binary_http/binary_http_message.h
@@ -23,7 +23,7 @@
 class QUICHE_EXPORT BinaryHttpMessage {
  public:
   // Name value pair of either a header or trailer field.
-  struct Field {
+  struct QUICHE_EXPORT Field {
     std::string name;
     std::string value;
     bool operator==(const BinaryHttpMessage::Field& rhs) const {
@@ -118,7 +118,7 @@
   //   scheme: HTTP
   //   authority: www.example.com
   //   path: /index.html
-  struct ControlData {
+  struct QUICHE_EXPORT ControlData {
     std::string method;
     std::string scheme;
     std::string authority;
@@ -172,7 +172,7 @@
   // A response can contain 0 to N informational responses.  Each informational
   // response contains a status code followed by a header field. Valid status
   // codes are [100,199].
-  class InformationalResponse {
+  class QUICHE_EXPORT InformationalResponse {
    public:
     explicit InformationalResponse(uint16_t status_code)
         : status_code_(status_code) {}