Qwant, Startpage links and popups do not work in private mode

[danishjafri88]

We should handle window.open when in private mode

Enhancement for #446 & #455:

What
In private mode the WKProcessPool of the WKWebViewConfiguration is overridden to avoid passing of cookies and other data between WKWebViews. This behaviour when combined with a popup ie window.open results in a crash

Why
When a window.open is called the parent WKWebView calls the delegate method:

optional public func webView(_ webView: WKWebView, createWebViewWith configuration: WKWebViewConfiguration, for navigationAction: WKNavigationAction, windowFeatures: WKWindowFeatures) -> WKWebView?

in WKUIDelegate. It provides a configuration for the new window. When in private mode, this configuration is altered resulting in corruption of configuration and subsequent crash.

Current-Fix
For now all popups are blocked when in private mode. (BrowserViewController.swift)
See: #456 (comment)

Enhancement
Two possible solutions:

1. Keep blocking popups and instead show an alert telling the user of the reason.
2. Intercept popup call in private mode, create a new tab (not a popup) with the same request and return nil. (What other info needs to be used from the callback can be discussed later.)

Description:

Steps to Reproduce

Actual result:

Expected result:

Reproduces how often: [Easily reproduced, Intermittent Issue]

Brave Version:

Device details:

Website problems only:

• did you check with Brave Shields down?
• did you check in Safari/Firefox (WkWebView-based browsers)?

Additional Information

[kylehickinson]

This affects one of the search engines we support, Startpage.com, which by default opens search results in a new window.

[jhreis]

Please see: #446 (comment) for rationale.

[srirambv]

• Verification passed on iPhone 7+ running 1.9(19.03.27.19)

  • Verified search results on Startpage and Qwant in private tabs load result in a new tab
  • Also verified steps from Brave crashes when we share video via Twitter option #446 description

• Verification passed on iPad Pro running 1.9(19.03.27.19)

  • Verified search results on Startpage and Qwant in private tabs load result in a new tab
  • Also verified steps from Brave crashes when we share video via Twitter option #446 description

• Verification passed on iPhone SE running 1.9 (19.03.27.19)

  • Verified search results on Startpage and Qwant in private tabs load result in a new tab
  • Also verified steps from Brave crashes when we share video via Twitter option #446 description

• Verification passed on iPad 5th Gen running 1.9 (19.03.27.19)

  • Verified search results on Startpage and Qwant in private tabs load result in a new tab
  • Also verified steps from Brave crashes when we share video via Twitter option #446 description

• Verification PASSED with 1.9 (19.3.27.19) on iPad Mini 4

  • Verified search results on Startpage and Qwant in private tabs load result in a new tab
  • Also verified steps from Brave crashes when we share video via Twitter option #446 description

• Verification passed on iPad 5th Gen running 1.9 (19.03.28.14)
• Verified search results on Startpage and Qwant in private tabs load result in a new tab
• Also verified steps from Brave crashes when we share video via Twitter option #446 description