Dispatch middle click manually by tracking mouse

chrome/browser/resources/ntp4/synthetic_middleclick.js

Index: chrome/browser/resources/ntp4/synthetic_middleclick.js
diff --git a/chrome/browser/resources/ntp4/synthetic_middleclick.js b/chrome/browser/resources/ntp4/synthetic_middleclick.js
new file mode 100644
index 0000000000000000000000000000000000000000..5ee4fab4a1c358e4a141f86f141f03d03dfddd83
--- /dev/null
+++ b/chrome/browser/resources/ntp4/synthetic_middleclick.js
@@ -0,0 +1,16 @@
+// Copyright (c) 2016 The Chromium Authors. All rights reserved.

[Lei Zhang, 2016/05/10 19:01:42]

no (c)

[Navid Zolghadr, 2016/05/10 19:28:26]

Done.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.

[Lei Zhang, 2016/05/10 19:01:42]

add blank line after.

[Navid Zolghadr, 2016/05/10 19:28:26]

Done.

+var middleButtonMouseDownTarget = null;
+document.addEventListener('mousedown', function(e) {
+  if (e.button == 1) {
+    middleButtonMouseDownTarget = e.target;
+  }
+}, true);
+document.addEventListener('mouseup', function(e) {
+  if (e.button == 1) {
+    if (e.target == middleButtonMouseDownTarget)
+      e.target.dispatchEvent(new MouseEvent('click', e));
+    middleButtonMouseDownTarget = null;
+  }
+}, true);