BundledExchanges: Require content-type header in non-empty responses

This reflects https://github.com/WICG/webpackage/pull/484.

Bug: 969596
Change-Id: I3484b6e76f51a76e507667499dddc37024cc0af7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1750528Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#686659}

services/data_decoder/bundled_exchanges_parser.cc

@@ -967,13 +967,7 @@ class BundledExchangesParser::ResponseParser
       return;
     }
 
-    // Step 9. "If headers does not contain a Content-Type header, return an
-    // error."
-
-    // TODO(crbug.com/966753): Implement this once
-    // https://github.com/WICG/webpackage/issues/445 is resolved.
-
-    // Step 10. "Let payloadLength be the result of getting the length of a CBOR
+    // Step 9. "Let payloadLength be the result of getting the length of a CBOR
     // bytestring header from stream (Section 3.5.2). If payloadLength is an
     // error, return that error."
     auto payload_length = input.ReadCBORHeader(CBORType::kByteString);
@@ -982,6 +976,15 @@ class BundledExchangesParser::ResponseParser
       return;
     }
 
+    // Step 10. "If payloadLength is greater than 0 and headers does not contain
+    // a Content-Type header, return an error."
+    if (*payload_length > 0 &&
+        !parsed_headers->headers.contains("content-type")) {
+      RunErrorCallbackAndDestroy(
+          "Non-empty response must have a content-type header.");
+      return;
+    }
+
     // Step 11. "If stream.currentOffset + payloadLength !=
     // requestMetadata.offset + requestMetadata.length, return an error."
     if (input.CurrentOffset() + *payload_length != response_length_) {

services/data_decoder/bundled_exchanges_parser_unittest.cc

@@ -443,6 +443,31 @@ TEST_F(BundledExchangeParserTest, InvalidHeaderValue) {
   ASSERT_FALSE(ParseResponse(&data_source, location));
 }
 
+TEST_F(BundledExchangeParserTest, NoContentTypeWithNonEmptyContent) {
+  BundleBuilder builder(kFallbackUrl, kManifestUrl);
+  builder.AddExchange("https://test.example.com/", {{":status", "200"}},
+                      "payload");
+  TestDataSource data_source(builder.CreateBundle());
+
+  mojom::BundleMetadataPtr metadata = ParseBundle(&data_source).first;
+  ASSERT_TRUE(metadata);
+  auto location = FindResponse(metadata, GURL("https://test.example.com/"));
+  ASSERT_TRUE(location);
+  ASSERT_FALSE(ParseResponse(&data_source, location));
+}
+
+TEST_F(BundledExchangeParserTest, NoContentTypeWithEmptyContent) {
+  BundleBuilder builder(kFallbackUrl, kManifestUrl);
+  builder.AddExchange("https://test.example.com/", {{":status", "301"}}, "");
+  TestDataSource data_source(builder.CreateBundle());
+
+  mojom::BundleMetadataPtr metadata = ParseBundle(&data_source).first;
+  ASSERT_TRUE(metadata);
+  auto location = FindResponse(metadata, GURL("https://test.example.com/"));
+  ASSERT_TRUE(location);
+  ASSERT_TRUE(ParseResponse(&data_source, location));
+}
+
 TEST_F(BundledExchangeParserTest, Variants) {
   BundleBuilder builder(kFallbackUrl, kManifestUrl);
   auto location1 = builder.AddResponse(