Revert "Use resource-level referrer policy for attributionsrc requests"

This reverts commit 4c4802b8681c23f09e62c1fb82ed2c00a65d12a6.

Reason for revert: Getting approvals on the revert in case launch approvals are not received in time.

Original change's description:
> Use resource-level referrer policy for attributionsrc requests
>
> For <img> and <script> the attributionsrc request's referrer policy now
> matches the subresource's policy, rather than the document-level
> default.
>
> For <a> and window.open, the attribution src request's referrer policy
> now matches that of the navigation, rather than the per-request default.
>
> WICG/attribution-reporting-api#382
> WICG/attribution-reporting-api#1254
>
> Change-Id: I763c055aef45fc17d41a3ba29b4f6ebfe24646cf
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5463164
> Reviewed-by: Dominic Farolino <dom@chromium.org>
> Reviewed-by: Nan Lin <linnan@chromium.org>
> Commit-Queue: Andrew Paseltiner <apaseltiner@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1294868}

Change-Id: I0b25937972ce74dc7519da5f2a6a2664d7ff6134

attribution-reporting/request-format.sub.https.html

@@ -53,7 +53,9 @@
   } else {
     assert_not_own_property(requests[0], 'attribution-reporting-eligible');
   }
+  assert_equals(requests[0].referer, location.toString());
 
+  // TODO(apaseltiner): Test various referrer policies.
   // TODO(apaseltiner): Test cookie propagation.
 
   const expectedURL = blankURL();

attribution-reporting/resources/helpers.js

@@ -171,7 +171,6 @@ const registerAttributionSrc = async ({
   extraQueryParams = {},
   reportingOrigin,
   extraHeaders = [],
-  referrerPolicy = '',
 }) => {
   const searchParams = new URLSearchParams(location.search);
 
@@ -202,6 +201,7 @@ const registerAttributionSrc = async ({
     headers.push({name, value: cookie});
   }
 
+
   let credentials;
   if (method === 'fetch') {
     const params = getFetchParams(reportingOrigin, cookie);
@@ -219,7 +219,6 @@ const registerAttributionSrc = async ({
   switch (method) {
     case 'img':
       const img = document.createElement('img');
-      img.referrerPolicy = referrerPolicy;
       if (eligible === null) {
         img.attributionSrc = url;
       } else {
@@ -237,7 +236,6 @@ const registerAttributionSrc = async ({
       return 'event';
     case 'script':
       const script = document.createElement('script');
-      script.referrerPolicy = referrerPolicy;
       if (eligible === null) {
         script.attributionSrc = url;
       } else {
@@ -251,7 +249,6 @@ const registerAttributionSrc = async ({
       return 'event';
     case 'a':
       const a = document.createElement('a');
-      a.referrerPolicy = referrerPolicy;
       a.target = '_blank';
       a.textContent = 'link';
       if (eligible === null) {
@@ -266,13 +263,12 @@ const registerAttributionSrc = async ({
       return 'navigation';
     case 'open':
       await test_driver.bless('open window', () => {
-        const feature = referrerPolicy === 'no-referrer' ? 'noreferrer' : '';
         if (eligible === null) {
           open(
               blankURL(), '_blank',
-              `attributionsrc=${encodeURIComponent(url)} ${feature}`);
+              `attributionsrc=${encodeURIComponent(url)}`);
         } else {
-          open(url, '_blank', `attributionsrc ${feature}`);
+          open(url, '_blank', 'attributionsrc');
         }
       });
       return 'navigation';
@@ -281,7 +277,7 @@ const registerAttributionSrc = async ({
       if (eligible !== null) {
         attributionReporting = JSON.parse(eligible);
       }
-      await fetch(url, {credentials, attributionReporting, referrerPolicy});
+      await fetch(url, {credentials, attributionReporting});
       return 'event';
     }
     case 'xhr':