Sync with 6fd10a34
Sync with 6fd10a34

Synced with dart-lang/site-webdev master branch, commit 6fd10a34:
https://github.com/dart-lang/site-webdev/tree/6fd10a34243bf254252b7d8dcbb885ef6bc59033/examples/ng/doc/hierarchical-dependency-injection

googlearchive/hierarchical-dependency-injection,googlearchive/hierarchical-dependency-injection,angular-examples/hierarchical-dependency-injection,angular-examples/hierarchical-dependency-injection