src/vs/workbench/contrib/files/browser/views/explorerViewer.ts/FilesFilter/filter
class FilesFilter:	filter(stat: ExplorerItem, parentVisibility: TreeVisibility): boolean {
		// Add newly visited .gitignore files to the ignore tree
		if (stat.name === '.gitignore' && this.ignoreTreesPerRoot.has(stat.root.resource.toString())) {
			this.processIgnoreFile(stat.root.resource.toString(), stat.resource, false);
			return true;
		}

		return this.isVisible(stat, parentVisibility);
	}