Switch to chaining API to match Ch 2. in book. (#335)
Switch to chaining API to match Ch 2. in book. (#335)

* Switch to chaining API to match Ch 2. in book.

tensorflow/tfjs-examples,tensorflow/tfjs-examples,tensorflow/tfjs-examples,tensorflow/tfjs-examples,tensorflow/tfjs-examples,tensorflow/tfjs-examples,tensorflow/tfjs-examples