Sync with 0b06912
Sync with 0b06912

Synced with dart-lang/site-webdev master branch, commit 0b06912:
https://github.com/dart-lang/site-webdev/tree/0b0691201d95ddf2bcd857029eb55fbdf026d813/examples/ng/doc/hierarchical-dependency-injection

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