Print a working hostname when running ts_devserver on crostini

Fixes https://github.com/angular/angular-bazel-example/issues/287

PiperOrigin-RevId: 240588105

devserver/main.go

diff --git a/devserver/main.go b/devserver/main.go
index 7b0a2a0..a41b899 100644
--- a/devserver/main.go
+++ b/devserver/main.go
@@ -16,7 +16,7 @@
 )
 
 var (
-	port            = flag.Int("port", 5432, "server port to listen on")
+	port = flag.Int("port", 5432, "server port to listen on")
 	// The "base" CLI flag is only kept because within Google3 because removing would be a breaking change due to
 	// ConcatJS and "devserver/devserver.go" still respecting the specified base flag.
 	base            = flag.String("base", "", "server base (required, runfiles of the binary)")
@@ -113,6 +113,12 @@
 	if err != nil {
 		h = "localhost"
 	}
+	// Detect if we are running in a linux container inside ChromeOS
+	// If so, we assume you want to use the native browser (outside the container)
+	// so you'll need to modify the hostname to access the server
+	if _, err := os.Stat("/etc/apt/sources.list.d/cros.list"); err == nil {
+		h = h + ".linux.test"
+	}
 
 	fmt.Printf("Server listening on http://%s:%d/\n", h, *port)
 	fmt.Fprintln(os.Stderr, http.ListenAndServe(fmt.Sprintf(":%d", *port), nil).Error())