[examples][components] Migrate to fuchsia-pkg URLs.

Remove legacy mode, add documentation for how to run example on command
line.

TEST=CQ and manual run.

SCN-1211 #done

Change-Id: I8d7616f04a19c1e934fe143877374a990aa01091
diff --git a/examples/ui/text_flutter/BUILD.gn b/examples/ui/text_flutter/BUILD.gn
index 20e755e..b5c8c50 100644
--- a/examples/ui/text_flutter/BUILD.gn
+++ b/examples/ui/text_flutter/BUILD.gn
@@ -5,8 +5,6 @@
 import("//topaz/runtime/flutter_runner/flutter_app.gni")
 
 flutter_app("text_flutter") {
-  deprecated_bare_package_url = "//build"
-
   main_dart = "lib/main.dart"
 
   sources = []
diff --git a/examples/ui/text_flutter/README.md b/examples/ui/text_flutter/README.md
new file mode 100644
index 0000000..d222964
--- /dev/null
+++ b/examples/ui/text_flutter/README.md
@@ -0,0 +1,8 @@
+# Text Input Example for Flutter
+
+## Usage
+
+```shell
+$ set_root_view fuchsia-pkg://fuchsia.com/text_flutter#meta/text_flutter.cmx
+```
+