BundledExchangesParser: Update the bundle format [1/2]

This updates BundledExchangesParser to parse the new bundle format [1].

Changes:
- Updated the magic header bytes [2]
- Version field is added (we use implementation-specific version string
  "b1\0\0", which matches gen-bundle's output [3])
- Fallback URL (== Primary URL) field is added
- ParseMetadata() returns error type ("format error" or "version error")
  and fallback URL if available
- Updated spec ref comments

The structure change of the index section is not reflected yet. It will
be updated in the next CL.

The test bundle file (hello.wbn) is generated with gen-bundle of
github.com/WICG/webpackage revision a3cef2c, which supports the new
bundle format except for the new index section structure.

[1] https://github.com/WICG/webpackage/pull/450
[2] https://github.com/WICG/webpackage/pull/454
[3] https://github.com/WICG/webpackage/pull/458

Bug: 969596
Change-Id: I95744ed00fdd09d369bb8648d1cdf62ca181d0dd
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1715487Reviewed-by: Robert Sesek <rsesek@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
Commit-Queue: Kunihiko Sakamoto <ksakamoto@chromium.org>
Cr-Commit-Position: refs/heads/master@{#684200}

content/browser/web_package/bundled_exchanges_reader_unittest.cc

@@ -163,7 +163,9 @@ class BundledExchangesReaderTest : public testing::Test {
     items.push_back(std::move(item));
 
     data_decoder::mojom::BundleMetadataPtr metadata =
-        data_decoder::mojom::BundleMetadata::New(std::move(items), GURL());
+        data_decoder::mojom::BundleMetadata::New(GURL() /* primary_url */,
+                                                 std::move(items),
+                                                 GURL() /* manifest_url */);
     factory_->RunMetadataCallback(std::move(metadata));
     run_loop.Run();
   }

services/data_decoder/public/cpp/safe_bundled_exchanges_parser.cc

@@ -60,7 +60,9 @@ void SafeBundledExchangesParser::ParseMetadata(
   // simultaneous request is fine enough.
   if (disconnected_ || !metadata_callback_.is_null()) {
     std::move(callback).Run(
-        nullptr, mojom::BundleMetadataParseError::New(kConnectionError));
+        nullptr, mojom::BundleMetadataParseError::New(
+                     mojom::BundleParseErrorType::kParserInternalError,
+                     GURL() /* fallback_url */, kConnectionError));
     return;
   }
   metadata_callback_ = std::move(callback);
@@ -78,7 +80,9 @@ void SafeBundledExchangesParser::ParseResponse(
   if (disconnected_ ||
       response_callbacks_.contains(response_callback_next_id_)) {
     std::move(callback).Run(
-        nullptr, mojom::BundleResponseParseError::New(kConnectionError));
+        nullptr, mojom::BundleResponseParseError::New(
+                     mojom::BundleParseErrorType::kParserInternalError,
+                     kConnectionError));
     return;
   }
   size_t callback_id = response_callback_next_id_++;
@@ -93,10 +97,14 @@ void SafeBundledExchangesParser::OnDisconnect() {
   disconnected_ = true;
   if (!metadata_callback_.is_null())
     std::move(metadata_callback_)
-        .Run(nullptr, mojom::BundleMetadataParseError::New(kConnectionError));
+        .Run(nullptr, mojom::BundleMetadataParseError::New(
+                          mojom::BundleParseErrorType::kParserInternalError,
+                          GURL() /* fallback_url */, kConnectionError));
   for (auto& callback : response_callbacks_)
     std::move(callback.second)
-        .Run(nullptr, mojom::BundleResponseParseError::New(kConnectionError));
+        .Run(nullptr, mojom::BundleResponseParseError::New(
+                          mojom::BundleParseErrorType::kParserInternalError,
+                          kConnectionError));
   response_callbacks_.clear();
 }
 

services/data_decoder/public/mojom/bundled_exchanges_parser.mojom

@@ -38,16 +38,26 @@ interface BundleDataSource {
   Read(uint64 offset, uint64 length) => (array<uint8>? buffer);
 };
 
+enum BundleParseErrorType {
+  kParserInternalError,
+  kFormatError,
+  kVersionError,
+};
+
 struct BundleMetadataParseError {
+  BundleParseErrorType type;
+  url.mojom.Url fallback_url;
   string message;
-  // TODO(crbug.com/969596): Add fields for error type and fallback URL.
 };
 
 struct BundleResponseParseError {
+  BundleParseErrorType type;
   string message;
 };
 
+// https://wicg.github.io/webpackage/draft-yasskin-wpack-bundled-exchanges.html#semantics-load-metadata
 struct BundleMetadata {
+  url.mojom.Url primary_url;
   array<BundleIndexItem> index;
   url.mojom.Url manifest_url;
 };

services/test/data/bundled_exchanges/generate-test-wbns.sh

@@ -12,7 +12,8 @@ if ! command -v gen-bundle > /dev/null 2>&1; then
     exit 1
 fi
 
-gen-bundle -baseURL https://test.example.org/ \
+gen-bundle -version b1 \
+           -baseURL https://test.example.org/ \
            -dir hello/ \
            -manifestURL manifest.webmanifest \
            -o hello.wbn