Add new balsa_frame microbenchmark This microbenchmark is very simple and tests the performance of parsing a chunked request with extensions with the strictest HttpValidationPolicy options available since they all add a bit of extra overhead. It also defines a nearly no-op visitor which should mimic the overhead required to invoke an integrators visitor implementation. A nearly identical test is added to balsa_frame_test.cc to test the correctness of the logic. All `_benchmark.cc` are already excluded by copybara rules. ``` Benchmarking blaze-out/k8-opt/bin/third_party/quiche/balsa/balsa_frame_benchmark Run on reubent3.cam (128 X 2695 MHz CPUs); 2026-02-11T17:21:00.272874364-05:00 CPU: AMD Rome (64 cores) dL1:32KB dL2:512KB dL3:256MB ***WARNING*** CPU scaling is enabled, the benchmark timings may be noisy, see http://go/benchmark#cpu-scaling Benchmark Time(ns) CPU(ns) Iterations ---------------------------------------------------------------------- BM_ProcessInputChunked 1703 1762 36579 5.334kB/s BM_ProcessInputChunked 1741 1629 31899 6.615kB/s BM_ProcessInputChunked 1721 1719 39511 5.061kB/s BM_ProcessInputChunked 1731 1718 39599 5.053kB/s BM_ProcessInputChunked 1689 1712 39726 5.053kB/s BM_ProcessInputChunked 1699 1642 31726 6.599kB/s BM_ProcessInputChunked 1686 1719 39580 5.053kB/s BM_ProcessInputChunked 1685 1711 39837 5.044kB/s BM_ProcessInputChunked 1693 1716 39636 5.053kB/s BM_ProcessInputChunked 1693 1710 39783 5.053kB/s BM_ProcessInputChunked 1711 1702 39922 5.060kB/s BM_ProcessInputChunked_mean 1704 1706 417798 5.315kB/s BM_ProcessInputChunked_stddev 17.9 33.2 417798 566.449B/s ``` Protected by adding google3 only performance test. PiperOrigin-RevId: 869351347

diff --git a/quiche/balsa/balsa_frame_test.cc b/quiche/balsa/balsa_frame_test.cc
index 1ff0488..3bf7873 100644
--- a/quiche/balsa/balsa_frame_test.cc
+++ b/quiche/balsa/balsa_frame_test.cc

@@ -5101,5 +5101,48 @@
   EXPECT_EQ(BalsaFrameEnums::BALSA_NO_ERROR, balsa_frame_.ErrorCode());
 }
 
+TEST_F(HTTPBalsaFrameTest, MostRestrictiveTest) {
+  BalsaFrame balsa_frame;
+  BalsaHeaders headers;
+  balsa_frame.set_is_request(true);
+  balsa_frame.set_balsa_headers(&headers);
+  balsa_frame.set_http_validation_policy(kMostStrictHttpValidationPolicy);
+
+  std::string message_headers =
+      "POST /search?q=benchy \t HTTP/1.1 \t \r\n"
+      "Transfer-Encoding:  chunked\r\n"
+      "header_1: a\r\n"
+      "header_2: b\r\n"
+      "header_3: c\r\n"
+      "header_4: d\r\n"
+      "header_5: e\r\n"
+      "\r\n";
+  std::string message_body =
+      "A;chunked_extension=\"foobar\"quote\"\"\r\n"
+      "0123456789\r\n"
+      "3f\r\n"
+      "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\r\n"
+      "2; chunked_extension=\"foobar\"quote\"\"\r\n"
+      "x \r\n"
+      "0; that's all folks\r\n";
+  std::string trailer_data =
+      "a_trailer_key: and a trailer value\r\n"
+      "\r\n";
+
+  std::string message =
+      absl::StrCat(message_headers, message_body, trailer_data);
+
+  size_t header_bytes_consumed =
+      balsa_frame.ProcessInput(message.data(), message.size());
+  EXPECT_EQ(header_bytes_consumed, message_headers.size());
+
+  size_t body_bytes_consumed = balsa_frame.ProcessInput(
+      message.data() + message_headers.size(), message.size());
+  EXPECT_EQ(body_bytes_consumed, message_body.size() + trailer_data.size());
+  EXPECT_TRUE(balsa_frame.MessageFullyRead());
+  EXPECT_FALSE(balsa_frame.Error());
+  EXPECT_EQ(balsa_frame.ErrorCode(), BalsaFrameEnums::BALSA_NO_ERROR);
+}
+
 }  // namespace
 }  // namespace quiche::test

diff --git a/quiche/balsa/http_validation_policy.h b/quiche/balsa/http_validation_policy.h
index fc5cd7e..a197071 100644
--- a/quiche/balsa/http_validation_policy.h
+++ b/quiche/balsa/http_validation_policy.h

@@ -176,6 +176,29 @@
   }
 };
 
+static constexpr HttpValidationPolicy kMostStrictHttpValidationPolicy = {
+    .disallow_header_continuation_lines = true,
+    .require_header_colon = true,
+    .disallow_multiple_content_length = true,
+    .disallow_transfer_encoding_with_content_length = true,
+    .validate_transfer_encoding = true,
+    .require_content_length_if_body_required = true,
+    .disallow_double_quote_in_header_name = true,
+    .disallow_invalid_header_characters_in_response = true,
+    .disallow_lone_cr_in_request_headers = true,
+    .disallow_lone_cr_in_chunk_extension = true,
+    .disallow_invalid_target_uris = true,
+    .sanitize_cr_tab_in_first_line =
+        quiche::HttpValidationPolicy::FirstLineValidationOption::SANITIZE,
+    .disallow_obs_text_in_field_names = true,
+    .disallow_lone_lf_in_chunk_extension = true,
+    .require_chunked_body_end_with_crlf_crlf = true,
+    .sanitize_firstline_spaces =
+        quiche::HttpValidationPolicy::FirstLineValidationOption::SANITIZE,
+    .sanitize_obs_fold_in_header_values = true,
+    .disallow_stray_data_after_chunk = true,
+    .disallow_invalid_request_methods = true};
+
 }  // namespace quiche
 
 #endif  // QUICHE_BALSA_HTTP_VALIDATION_POLICY_H_