Keyboard isn't dismissed when another website is loaded

[Michael Sheldon]

Steps to reproduce:

 1. Open a website with an input field which redirects the user to another website after pressing a button (google.com, duckduckgo.com, Twitter's "New Tweet" page, developer.ubuntu.com, etc.)

 2. Click on the input field (this will open the keyboard)

 3. Either press the ("search") button which will redirect you to another page or press the webbrowser's back button

Expected result:

 Keyboard should be dismissed when the new page is loaded

Actual result:

 Keyboard is still visible. If the keyboard is then dismissed by swiping it will reappear as soon as the user touches the webview (e.g. to scroll).

 If the user closes the keyboard manually before the new page has been loaded, it will stay closed.
 If the user opens the tab overview with the keyboard open due to this bug, it will stay open, while closing the tab or switching to another tab will also dismiss the keyboard until the user switches back to the tab where the issue occured.
 Selecting another input field on the newly opened page allows you to finally dismiss the keyboard.

 Therefore, it seems as if the input field on the previous page is still focused in the background.

[Olivier Tilloy (osomon)]

Tentatively adding an oxide task, as it’s likely that the issue is there.

[Niklas Wenzel (nikwen)]

I hope you don't mind that I rephrased this bug in a more general way.