[tests] Convert a detached typed array to a null string

third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html

Index: third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html
diff --git a/third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html b/third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html
index 7f2eeb862d6f04d195080454b4b5b4c2425f5aeb..ec936fb5008f3e96e82d3cb3c3666c1939d5e553 100644
--- a/third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html
+++ b/third_party/WebKit/LayoutTests/fast/dom/Window/window-postmessage-args.html
@@ -35,14 +35,21 @@ function tryPostMessageFunction(postMessageFunction, first, second, third, shoul
         pass = shouldFail;
         reason = ": threw exception " + e;
     }
+    // we cannot convert detached typed arrays into strings, thus
+    // manually convert detached typed arrays into a null string.
+    if (first instanceof Int8Array && first.byteLength === 0)
+        first = "";
+    for (var i = 0; third && i < third.length; i++) {
+        if (third[i] instanceof Int8Array && third[i].byteLength === 0)
+            third[i] = "";
+    }

[Dan Ehrenberg, 2017/04/11 10:20:22]

Nit: this code could be slightly cleaned up, and clarified in the test results
what's going on (you would need test expectation updates), with something like

function convertDetached(obj) {
  // Represent detached TypedArrays as ""
  if (obj instanceOf Int8Array && obj.byteLength === 0)
    return "[detached TypedArray]";
  return obj;
}

testPassed("Posting message ('" + convertDetached(first) + "', " +
third.map(convertDetached) + ")" + reason);

[Choongwoo Han, 2017/04/11 12:48:23]

Done.

     if (pass)
         testPassed("Posting message ('" + first + "', " + third + ")" + reason);
     else
         testFailed("Posting message ('" + first + "', " + third + ")" + reason);
 }
 
-function tryPostMessage(first, second, third, shouldFail) {
-    tryPostMessageFunction(window.postMessage, first, second, third, shouldFail);
+function tryPostMessage(first, second, third, shouldFail) { tryPostMessageFunction(window.postMessage, first, second, third, shouldFail);

[Dan Ehrenberg, 2017/04/11 10:20:22]

Nit: Undo this whitespace change.

[Choongwoo Han, 2017/04/11 12:48:23]

Done.

 }
 
 document.getElementById("description").innerHTML = "Test that the second argument of window.postMessage is ignored or triggers an error if it is not a message port. You should see PASS message '1' through '7', followed by 'done', with messages 4-7 received below.<br><br>";