Inject/Provide not working in Vue.extend() class.

[SpringNyan]

Version

2.4.2

Reproduction link

https://jsfiddle.net/50wL7mdz/55826/

Steps to reproduce

1. Use Vue.extend() to create a subclass which contains provide option.
2. Inject property in child component of subclass.

What is expected?

Property is injected correctly.

What is actually happening?

Property is not injected.

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In src/core/util/options.js, Line 97-99. defaultData is set to undefined if parentVal is not a function. It may cause this issue.