[Zelenium] Store the test HTML as a dataURL in case of error

This will ease debugging from posted test results.
This code should be synchronous (no Blob asDataURL method for example) and so, btoa is used.

Sadly, btoa will fail with unicode character
Do not report HTML error in such case, until a cleaner dataURL is implemented

product/Zelenium/selenium/core/scripts/selenium-testrunner.js

@@ -499,6 +499,19 @@ objectExtend(HtmlTestCaseRow.prototype, {
     markFailed: function(errorMsg) {
         AbstractResultAwareRow.prototype.markFailed.call(this, errorMsg);
         this.setMessage(errorMsg);
+
+        // Store the test HTML as a dataURL to ease debugging from posted test results
+        // This code should be synchronous (no Blob asDataURL method for example)
+        var aElement = this.trElement.ownerDocument.createElement("a");
+        aElement.textContent = ' (HTML)'
+        try {
+          aElement.href = 'data:text/html;base64,' + btoa(sel$('selenium_myiframe').contentWindow.document.body.innerHTML);
+          this.trElement.cells[2].appendChild(aElement);
+        } catch (error) {
+          // btoa will fail with unicode character
+          // Do not report HTML error in such case, until a cleaner dataURL is implemented
+          ;
+        }
     },
 
     setMessage: function(message) {