Add response status code to PerfomanceResourceTiming (#335)

* Response status field behind CORS check

* Add note mentioning opaque filtered response

* Update index.html

* Amend note

Author: abinpaul1

index.html

@@ -371,6 +371,7 @@ <h3>
               readonly attribute unsigned long long  transferSize;
               readonly attribute unsigned long long  encodedBodySize;
               readonly attribute unsigned long long  decodedBodySize;
+              readonly attribute unsigned short responseStatus;
               readonly attribute RenderBlockingStatusType renderBlockingStatus;
               [Default] object toJSON();
           };
@@ -401,6 +402,11 @@ <h3>
           info=] <a data-dfn-for="PerformanceResourceTiming"><dfn>resource
           info</dfn></a>.
         </p>
+        <p>
+          A <a>PerformanceResourceTiming</a> has an associated
+          <a data-cite="FETCH#concept-status">status</a> <a data-dfn-for=
+          "PerformanceResourceTiming"><dfn>response status</dfn></a>.
+        </p>
         <p>
           A <a>PerformanceResourceTiming</a> has an associated
           {{RenderBlockingStatusType}} <a data-dfn-for=
@@ -701,6 +707,16 @@ <h3>
             </p>
           </li>
         </ol>
+        <p data-dfn-for="PerformanceResourceTiming">
+          The <dfn>responseStatus</dfn> getter steps are to return
+          <a>this</a>'s <a data-for="PerformanceResourceTiming">response status</a>.
+        </p>
+        <p class='note'>
+          `responseStatus` is determined in [=Fetch=]. For a cross-origin
+          <a data-cite="FETCH#dom-requestmode-no-cors">no-cors</a> request it
+          would be 0 because the response would be an <a data-cite=
+          "FETCH#concept-filtered-response-opaque">opaque filtered response</a>.
+        </p>
         <p data-dfn-for="PerformanceResourceTiming">
           The <dfn>renderBlockingStatus</dfn> getter steps are to return
           <a data-link-for="RenderBlockingStatusType">blocking</a> if
@@ -1107,17 +1123,18 @@ <h2>
           To <dfn data-export="">mark resource timing</dfn> given a [=/fetch
           timing info=] |timingInfo|, a DOMString |requestedURL|, a DOMString
           |initiatorType| a <a>global object</a> |global|, a string
-          |cacheMode|, and a [=/response body info=] |bodyInfo|, perform the
-          following steps:
+          |cacheMode|, a [=/response body info=] |bodyInfo|, and a
+          <a data-cite="FETCH#concept-status">status</a> |responseStatus|,
+          perform the following steps:
         </p>
         <ol>
           <li>Create a <a>PerformanceResourceTiming</a> object |entry| in
           |global|'s [=global object/realm=].
           </li>
           <li>
             <a>Setup the resource timing entry</a> for |entry|, given
-            |initiatorType|, |requestedURL|, |timingInfo|, |cacheMode|, and
-            |bodyInfo|.
+            |initiatorType|, |requestedURL|, |timingInfo|, |cacheMode|,
+            |bodyInfo| and |responseStatus|.
           </li>
           <li>
             <a data-cite=
@@ -1134,8 +1151,9 @@ <h2>
           To <dfn data-export="">setup the resource timing entry</dfn> for
           <a>PerformanceResourceTiming</a> |entry| given DOMString
           |initiatorType|, DOMString |requestedURL|, [=/fetch timing info=]
-          |timingInfo|, a DOMString |cacheMode|, and a [=response body info=]
-          |bodyInfo|, perform the following steps:
+          |timingInfo|, a DOMString |cacheMode|, a [=response body info=]
+          |bodyInfo|, and a <a data-cite="FETCH#concept-status">status</a>
+          |responseStatus|, perform the following steps:
         </p>
         <ol>
           <li>Assert that |cacheMode| is the empty string,
@@ -1156,6 +1174,9 @@ <h2>
           <li>Set |entry|'s <a data-for="PerformanceResourceTiming">cache
           mode</a> to |cacheMode|.
           </li>
+          <li>Set |entry|'s <a data-for="PerformanceResourceTiming">response
+          status</a> to |responseStatus|.
+          </li>
         </ol>
         <p>
           To <dfn>convert fetch timestamp</dfn> given {{DOMHighResTimeStamp}}