Add code-sample integration tests
Add code-sample integration tests

google/playground-elements,PolymerLabs/playground-elements,google/playground-elements,PolymerLabs/code-sample-editor-package,PolymerLabs/code-sample-editor,PolymerLabs/playground-elements,PolymerLabs/playground-elements,PolymerLabs/code-sample-editor,PolymerLabs/code-sample-editor-package,PolymerLabs/code-sample-editor-package,google/playground-elements,PolymerLabs/code-sample-editor