Remove webkitdropzone.

third_party/WebKit/LayoutTests/fast/dnd/resources/dropEffect-common.js

+const mouseMoveToCenter = element => {
+  const clientRect = element.getBoundingClientRect();
+  const centerX = (clientRect.left + clientRect.right) / 2;
+  const centerY = (clientRect.top + clientRect.bottom) / 2;
+  eventSender.mouseMoveTo(centerX, centerY);
+};
+
+const dropEffectTest = testCase => {
+  let gotDrop = false;
+  promise_test(t => new Promise((resolve, reject) => {
+    document.querySelector('#test-description').textContent =
+        JSON.stringify(testCase);
+
+    const dragged = document.querySelector('.dragged');
+    if (dragged && !dragged.classList.contains('no-ondragstart')) {
+      dragged.ondragstart = t.step_func(event => {
+        event.dataTransfer.setData('text/plain', 'Needed to work in Firefox');
+        if ('allowed' in testCase)
+          event.dataTransfer.effectAllowed = testCase.allowed;
+      });
+    }
+
+    const dropZone = document.querySelector('.dropzone');
+    dropZone.ondragover = t.step_func(event => {
+      event.preventDefault();
+      if ('drop' in testCase)
+        event.dataTransfer.dropEffect = testCase.drop;
+    });
+    dropZone.ondrop = t.step_func(event => {
+      event.preventDefault();
+      gotDrop = true;
+    });
+
+    const doneButton = document.querySelector('.done');
+
+    if (dragged) {
+      dragged.ondragend = t.step_func(event => {
+        resolve(event.dataTransfer.dropEffect);
+      });
+    } else {
+      doneButton.onclick = t.step_func(() => {
+        resolve('none');
+      });
+    }
+
+    if (window.eventSender) {
+      if (dragged) {
+        mouseMoveToCenter(dragged);
+        eventSender.mouseDown();
+      } else {
+        eventSender.mouseMoveTo(0, 0);
+        eventSender.beginDragWithFiles(['resources/dragged-file.txt']);
+      }
+      setTimeout(() => {
+        mouseMoveToCenter(dropZone);
+        eventSender.mouseUp();
+        if (doneButton) {
+          setTimeout(() => {
+            const clickEvent = new Event('click');
+            doneButton.dispatchEvent(clickEvent);
+          }, 100);
+        }
+      }, 100);
+    }
+  }).then(dragOperation => {
+    if ('operation' in testCase) {
+      assert_true(gotDrop, 'drop target should have received a drop event');
+      assert_equals(dragOperation, testCase.operation);
+    } else {
+      assert_true(
+          !gotDrop, 'drop target should not have received a drop event');
+      assert_equals(dragOperation, 'none');
+    }
+  }), `effectAllowed: ${testCase.allowed} dropEffect: ${testCase.drop}`);
+};
+
+const dropEffectTests = testCases => {
+  for (let testCase of testCases)
+    dropEffectTest(testCase);
+
+  promise_test(t => {
+    return Promise.resolve().then(() => {
+      document.querySelector('#test-description').textContent = 'done';
+    });
+  }, 'all tests complete');
+}