Vue.config.performance can't work

[dear-lizhihua]

https://jsfiddle.net/50wL7mdz/94913/

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[yyx990803]

Thanks for the PR - note you can inspect the timeline by using Chrome devtool's performance recording and see the results in "User Timing". We are clearing the marks and measures because the API documentation seems to recommend that as good practice for saving memory. In practice, since this piece of code only gets called during development, it's probably fine to leave the measure entries. (mark entries are not that useful)

We will include it in 2.6.