src/vs/workbench/api/common/extHostLanguageFeatures.ts/ExtHostLanguageFeatures/$provideDeclaration
class ExtHostLanguageFeatures:	$provideDeclaration(handle: number, resource: UriComponents, position: IPosition, token: CancellationToken): Promise<languages.LocationLink[]> {
		return this._withAdapter(handle, DeclarationAdapter, adapter => adapter.provideDeclaration(URI.revive(resource), position, token), [], token);
	}