Launch the following pages with new task flag.

Third-party
Google legal
System WebView

Based on the large screen design, those pages should be launched as
a new task to fulfill the new UI design.

Fix: 197701608
Fix: 197701739
Fix: 197702148
Test: Manually test the UI
Change-Id: Ia1d3a6f99a022f42dc0ee082ae3bf27f89db3cbc