add scopeId to components in component

[hareku]

No description provided.

[yyx990803]

I think it's questionable whether we want to keep this behavior, as it has led to confusing behavior in the past, e.g. a parent scope rule accidentally affecting the child because the child root happens to have the same class name:

In parent:

<template>
  <Child />
</template>

<style scoped>
.foo { color: red }
</style>

In child:

<template>
  <div class="foo">hello</div>
</template>

---

IMO if the parent wants to explicitly style the child root it should use a deep selector.

Of course, removing this behavior would be a breaking change, and we should probably add it to this RFC.

[yyx990803]

I'll merge this since this keeps the behavior consistent with 2.x. We will revisit the change as part of the RFC discussion.

[hareku]

@yyx990803
Thank you refactor and merge it.