Add tests for retargeted event.target in LayoutTests/shadow-dom/

third_party/WebKit/LayoutTests/shadow-dom/resources/shadow-dom.js

 function removeWhiteSpaceOnlyTextNodes(node)
 {
     for (var i = 0; i < node.childNodes.length; i++) {
         var child = node.childNodes[i];
         if (child.nodeType === Node.TEXT_NODE && child.nodeValue.trim().length == 0) {
             node.removeChild(child);
             i--;
         } else if (child.nodeType === Node.ELEMENT_NODE || child.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
             removeWhiteSpaceOnlyTextNodes(child);
         }
@@ skipping 104 matching lines @@
   for (let label in nodes) {
     let startingNode = nodes[label];
     for (let node = startingNode; node; node = node.parentNode) {
       if (attachedNodes.indexOf(node) >= 0)
         continue;
       let id = node.id;
       if (!id)
         continue;
       attachedNodes.push(node);
       node.addEventListener(event.type, (e) => {
+        // Record [currentTarget, target, relatedTarget, composedPath()]
         log.push([id,
+                  labelFor(e.target),
                   e.relatedTarget ? labelFor(e.relatedTarget) : null,
                   e.composedPath().map((n) => {
                     return labelFor(n);
                   })]);
       });
     }
   }
   target.dispatchEvent(event);
   return log;
 }
 
+// TODO(hayato): Merge this into dispatchEventWithLog
 function dispatchUAEventWithLog(nodes, target, eventType, callback) {
 
   function labelFor(e) {
     return e.id || e.tagName;
   }
 
   let log = [];
   let attachedNodes = [];
   for (let label in nodes) {
     let startingNode = nodes[label];
     for (let node = startingNode; node; node = node.parentNode) {
       if (attachedNodes.indexOf(node) >= 0)
         continue;
       let id = node.id;
       if (!id)
         continue;
       attachedNodes.push(node);
       node.addEventListener(eventType, (e) => {
+        // Record [currentTarget, target, relatedTarget, composedPath()]
         log.push([id,
+                  labelFor(e.target),
                   e.relatedTarget ? labelFor(e.relatedTarget) : null,
                   e.composedPath().map((n) => {
                     return labelFor(n);
                   })]);
       });
     }
   }
   callback(target);
   return log;
 }
 
-function makeExpectedEventPathLog(path) {
-  let expectedLog = [];
-  for (let i of path) {
-    expectedLog.push([i, null, path]);
-  }
-  return expectedLog;
-}
-
 function debugEventLog(log) {
   for (let i = 0; i < log.length; i++) {
-    console.log('[' + i + '] currentTarget: ' + log[i][0] + ' relatedTarget: ' + log[i][1] + ' composedPath(): ' + log[i][2]);
+    console.log('[' + i + '] currentTarget: ' + log[i][0] + ' target: ' + log[i][1] + ' relatedTarget: ' + log[i][2] + ' composedPath(): ' + log[i][3]);
   }
 }
 
 function debugCreateTestTree(nodes) {
   for (let k in nodes) {
     console.log(k + ' -> ' + nodes[k]);
   }
 }
 
 // This function assumes that testharness.js is available.
 function assert_event_path_equals(actual, expected) {
   assert_equals(actual.length, expected.length);
   for (let i = 0; i < actual.length; ++i) {
     assert_equals(actual[i][0], expected[i][0], 'currentTarget at ' + i + ' should be same');
-    assert_equals(actual[i][1], expected[i][1], 'relatedTarget at ' + i + ' should be same');
-    assert_array_equals(actual[i][2], expected[i][2], 'composedPath at ' + i + ' should be same');
+    assert_equals(actual[i][1], expected[i][1], 'target at ' + i + ' should be same');
+    assert_equals(actual[i][2], expected[i][2], 'relatedTarget at ' + i + ' should be same');
+    assert_array_equals(actual[i][3], expected[i][3], 'composedPath at ' + i + ' should be same');
   }
 }