Webview reload / context reset hook

[breautek]

A hook / observable event for when the webview / JS state is reloaded can be important for plugins that manages native assets.

A reloaded webview may lose handles responsible for managing native resources. E.g. a native view, whose view will remain in view until it is cleaned up. Reloading the webview however causes the handle to be lost.

A hook would allow plugins to cleanup these resources for when something reloads the webview either via:

• window.location.href
• window.location.reload
• Triggering a refresh via ctrl/cmd + r through the web inspector.