Allow debug adapters to customize the behavior of the 'restart' button

[roblourens]

For the chrome debugging extension, it would be much more useful if the debug 'restart' button/action could refresh the page. This could be implemented by the debug adapter. For other cases, the current behavior should be kept where vscode shuts down/restarts the debug adapter. Is this generic enough to be part of the debug protocol?

[weinand]

@roblourens yes, that makes a lot of sense (and we were discussing this use case already when implementing the current 'restart' functionality).
I'll come up with a proposal.

[weinand]

I've added a restart request to the protocol and a corresponding supportsRestartRequest capability.

@isidorn please adopt this by calling the restart request if supportsRestartRequest is true (and skip the default implementation that terminates the adapter and launches it anew).

[weinand]

@roblourens please adopt this feature in the Debugger for Chrome.