Start sending auxclick instead of click for non-primary buttons

third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js

Index: third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js
diff --git a/third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js b/third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js
index d6e750235a1f50e84fef75bf159d44e74f8cff35..a6defdf765d380f487ea84609bdde208dc75c77b 100644
--- a/third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js
+++ b/third_party/WebKit/Source/devtools/front_end/ui/TabbedPane.js
@@ -1081,6 +1081,7 @@ WebInspector.TabbedPaneTab.prototype = {
             tabElement.classList.add("measuring");
         } else {
             tabElement.addEventListener("click", this._tabClicked.bind(this), false);
+            tabElement.addEventListener("auxclick", this._tabClicked.bind(this), false);

[dgozman, 2016/08/03 20:54:28]

I took a closer look, and now I think that we can probably regress closing tabs
with middle click behavior for legacy frontends - it's not a very big deal. This
means we could avoid polyfill entirely.

On a side note though, how did you find all the places which have to be fixed?
I'm worried that it's easy to miss them.

[Navid Zolghadr, 2016/08/03 21:35:20]

Awesome. Then I will get rid of that polyfill.
Regarding whether I covered all the usecases or not previously I broke this
behavior and listed all the regressions it caused as blocking bugs for
http://crbug.com/255. Also I did some code search over button checks and
basically fixed them all here in this patch. I will continue monitoring if
anything comes up and will fix that. Note that this feature will remain behind
experimental flag for some time just to make sure everything is fine.

[dgozman, 2016/08/03 22:31:49]

Thanks for explanation.

             tabElement.addEventListener("mousedown", this._tabMouseDown.bind(this), false);
             tabElement.addEventListener("mouseup", this._tabMouseUp.bind(this), false);