Allow trailing headers with duplicate keys. Protected by FLAGS_quic_reloadable_flag_quic_allow_dupl…

net/quic/core/spdy_utils_test.cc

Index: net/quic/core/spdy_utils_test.cc
diff --git a/net/quic/core/spdy_utils_test.cc b/net/quic/core/spdy_utils_test.cc
index b5978aa74c44425a85ce56b979bc129b4dbdc39d..6acfc83d01b987b2bbcc754e916ac399f2e01046 100644
--- a/net/quic/core/spdy_utils_test.cc
+++ b/net/quic/core/spdy_utils_test.cc
@@ -6,6 +6,8 @@
 #include <memory>
 
 #include "base/macros.h"
+#include "net/quic/platform/api/quic_flag_utils.h"
+#include "net/quic/platform/api/quic_flags.h"
 #include "net/quic/platform/api/quic_string_piece.h"
 #include "net/quic/platform/api/quic_text_utils.h"
 #include "net/test/gtest_util.h"
@@ -246,7 +248,10 @@ TEST(CopyAndValidateTrailers, PseudoHeaderInTrailers) {
 }
 
 TEST(CopyAndValidateTrailers, DuplicateTrailers) {
-  // Duplicate trailers are not allowed.
+  // Duplicate trailers are allowed, and their values are concatenated into a
+  // single string delimted with '\0'. Some of the duplicate headers
+  // deliberately have an empty value.
+  FLAGS_quic_reloadable_flag_quic_handle_duplicate_trailers = true;
   auto trailers = FromList({{"key", "value0"},
                             {"key", "value1"},
                             {"key", ""},
@@ -258,8 +263,38 @@ TEST(CopyAndValidateTrailers, DuplicateTrailers) {
                             {"key", "non_contiguous_duplicate"}});
   size_t final_byte_offset = 0;
   SpdyHeaderBlock block;
-  EXPECT_FALSE(SpdyUtils::CopyAndValidateTrailers(*trailers, &final_byte_offset,
-                                                  &block));
+  EXPECT_TRUE(SpdyUtils::CopyAndValidateTrailers(*trailers, &final_byte_offset,
+                                                 &block));
+  EXPECT_THAT(
+      block,
+      UnorderedElementsAre(
+          Pair("key",
+               QuicStringPiece(
+                   "value0\0value1\0\0\0value2\0\0non_contiguous_duplicate",
+                   48)),
+          Pair("other_key", "value")));
+}
+
+TEST(CopyAndValidateTrailers, DuplicateCookies) {
+  // Duplicate cookie headers in trailers should be concatenated into a single
+  //  "; " delimted string.
+  FLAGS_quic_reloadable_flag_quic_handle_duplicate_trailers = true;
+  auto headers = FromList({{"cookie", " part 1"},
+                           {"cookie", "part 2 "},
+                           {"cookie", "part3"},
+                           {"key", "value"},
+                           {kFinalOffsetHeaderKey, "1234"},
+                           {"cookie", " non_contiguous_cookie!"}});
+
+  size_t final_byte_offset = 0;
+  SpdyHeaderBlock block;
+  EXPECT_TRUE(
+      SpdyUtils::CopyAndValidateTrailers(*headers, &final_byte_offset, &block));
+  EXPECT_THAT(
+      block,
+      UnorderedElementsAre(
+          Pair("cookie", " part 1; part 2 ; part3;  non_contiguous_cookie!"),
+          Pair("key", "value")));
 }
 
 TEST(GetUrlFromHeaderBlock, Basic) {