[Background Fetch] Enable creating registrations with duplicate requests

Remove check in renderer and add WP test for uploads.

Bug: 871174
Change-Id: Id225cc05b6f3c065962e1481c98562ca96d87322
Reviewed-on: https://chromium-review.googlesource.com/c/1424821
Commit-Queue: Rayan Kanso <rayankans@chromium.org>
Reviewed-by: Mugdha Lakhani <nator@google.com>
Reviewed-by: Peter Beverloo <peter@chromium.org>
Cr-Commit-Position: refs/heads/master@{#625640}

third_party/blink/renderer/modules/background_fetch/background_fetch_manager.cc

@@ -245,24 +245,8 @@ ScriptPromise BackgroundFetchManager::fetch(
     kurls.insert(request_url);
   }
 
-  const bool has_duplicate_requests = kurls.size() != fetch_api_requests.size();
-
   UMA_HISTOGRAM_BOOLEAN("BackgroundFetch.HasDuplicateRequests",
-                        has_duplicate_requests);
-
-  // Note: This is a proprietary check, due to the way Chrome currently handles
-  // storing background fetch records. Entries are keyed by the URL, so if two
-  // requests have the same URL, and different responses, the first response
-  // will be lost when the second request/response pair is stored.
-  if (has_duplicate_requests) {
-    return ScriptPromise::Reject(
-        script_state,
-        V8ThrowException::CreateTypeError(
-            script_state->GetIsolate(),
-            "Fetches with duplicate requests are not yet supported. "
-            "Consider adding query params to make the requests unique. "
-            "For updates check http://crbug.com/871174"));
-  }
+                        kurls.size() != fetch_api_requests.size());
 
   ScriptPromiseResolver* resolver = ScriptPromiseResolver::Create(script_state);
   ScriptPromise promise = resolver->Promise();

third_party/blink/web_tests/external/wpt/background-fetch/fetch-uploads.https.window.js

@@ -44,3 +44,21 @@ backgroundFetchTest(async (test, backgroundFetch) => {
 
   assert_equals(uploaded, uploadData.length);
 }, 'Progress event includes uploaded bytes');
+
+backgroundFetchTest(async (test, backgroundFetch) => {
+  const uploadRequest1 =
+      new Request('resources/upload.py', {method: 'POST', body: 'upload1'});
+  const uploadRequest2 =
+      new Request('resources/upload.py', {method: 'POST', body: 'upload2'});
+
+  await backgroundFetch.fetch(uniqueId(), [uploadRequest1, uploadRequest2]);
+
+  const {type, eventRegistration, results} = await getMessageFromServiceWorker();
+  assert_equals(type, 'backgroundfetchsuccess');
+  assert_equals(results.length, 2);
+  assert_equals(eventRegistration.result, 'success');
+  assert_equals(eventRegistration.failureReason, '');
+
+  assert_array_equals([results[0].text, results[1].text].sort(),
+                      ['upload1', 'upload2']);
+}, 'Duplicate upload requests work and can be distinguished.');

third_party/blink/web_tests/external/wpt/background-fetch/fetch.https.window-expected.txt

@@ -8,7 +8,7 @@ FAIL Requests with text/json content type require CORS Preflight and succeed. as
 PASS Using Background Fetch to successfully fetch a single resource
 PASS Registration object gets updated values when a background fetch completes.
 PASS Background Fetch that exceeds the quota throws a QuotaExceededError
-FAIL Fetches can have requests with duplicate URLs promise_test: Unhandled rejection with value: object "TypeError: Fetches with duplicate requests are not yet supported. Consider adding query params to make the requests unique. For updates check http://crbug.com/871174"
+PASS Fetches can have requests with duplicate URLs
 PASS recordsAvailable is false after onbackgroundfetchsuccess finishes execution.
 PASS Using Background Fetch to fetch a non-existent resource should fail.
 PASS Fetches with mixed content should fail.