Android : setBuiltInZoomControls with WebView inside of PopupWindow

I have a PopupWindow that displays a WebView on a button press. If setBuiltInZoomControls is set to false, the WebView displays the page as expected. However, if setBuiltInZoomControls is set to true, any interaction with the WebView (Scrolling, pinch-zooming) causes an error.

Here is the Error:

E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example.******, PID: 19046
    android.view.WindowManager$BadTokenException: Unable to add window -- token android.view.ViewRootImpl$W@4241c6c0 is not valid; is your activity running?
            at android.view.ViewRootImpl.setView(ViewRootImpl.java:748)
            at android.view.WindowManagerGlobal.addView(WindowManagerGlobal.java:278)
            at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:69)
            at android.widget.ZoomButtonsController.setVisible(ZoomButtonsController.java:373)
            at com.android.org.chromium.android_webview.AwZoomControls.invokeZoomPicker(AwZoomControls.java:28)
            at com.android.org.chromium.content.browser.ContentViewCore.invokeZoomPicker(ContentViewCore.java:2607)
            at com.android.org.chromium.content.browser.ContentViewGestureHandler$1.onScroll(ContentViewGestureHandler.java:429)
            at com.android.org.chromium.content.browser.third_party.GestureDetector.onTouchEvent(GestureDetector.java:594)
            at com.android.org.chromium.content.browser.ContentViewGestureHandler.processTouchEvent(ContentViewGestureHandler.java:970)
            at com.android.org.chromium.content.browser.ContentViewGestureHandler.onTouchEvent(ContentViewGestureHandler.java:802)
            at com.android.org.chromium.content.browser.ContentViewCore.onTouchEvent(ContentViewCore.java:1244)
            at com.android.org.chromium.android_webview.AwContents.onTouchEvent(AwContents.java:1523)
            at com.android.webview.chromium.WebViewChromium.onTouchEvent(WebViewChromium.java:1833)
            at android.webkit.WebView.onTouchEvent(WebView.java:2167)
            at android.view.View.dispatchTouchEvent(View.java:8115)
            at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2405)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2129)
            at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2411)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2144)
            at android.view.ViewGroup.dispatchTransformedTouchEvent(ViewGroup.java:2411)
            at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:2144)
            at android.widget.PopupWindow$PopupViewContainer.dispatchTouchEvent(PopupWindow.java:1979)
            at android.view.View.dispatchPointerEvent(View.java:8323)
            at android.view.ViewRootImpl$ViewPostImeInputStage.processPointerEvent(ViewRootImpl.java:4623)
            at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:4491)
            at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4049)
            at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4103)
            at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4072)
            at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:4183)
            at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4080)
            at android.view.ViewRootImpl$AsyncInputStage.apply(ViewRootImpl.java:4240)
            at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4049)
            at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:4103)
            at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:4072)
            at android.view.ViewRootImpl$InputStage.apply(ViewRootImpl.java:4080)
            at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:4049)
            at android.view.ViewRootImpl.deliverInputEvent(ViewRootImpl.java:6415)
            at android.view.ViewRootImpl.doProcessInputEvents(ViewRootImpl.java:6334)
            at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6305)
            at android.view.ViewRootImpl.enqueueInputEvent(ViewRootImpl.java:6270)
            at android.view.ViewRootImpl$WindowInputEventReceiver.onInputEvent(ViewRootImpl.java:6495)
            at android.view.InputEventReceiver.dispatchInputEvent(InputEventReceiver.java:185)
            at android.view.InputEventReceiver.nativeConsumeBatchedInputEvents(Native Method)
            at android.view.InputEventReceiver.consumeBatchedInputEvents(InputEventReceiver.java:176)
            at android.view.ViewRootImpl.doConsumeBatchedInput(ViewRootImpl.java:6468)
            at android.view.ViewRootImpl$ConsumeBatchedInputRunnable.run(ViewRootImpl.java:6514)
            at android.view.Choreographer$CallbackRecord.run(Choreographer.java: