UIViewRoot.createUniqueId() should generate unique ids for all the component tree.

In JSF 2.2 spec there is a change related to UIViewRoot.createUniqueId(). The javadoc says this:

"... Generate an identifier for a component. The identifier will be prefixed with UNIQUE_ID_PREFIX, and will be unique within the non-NamingContainer child sub-trees of this UIViewRoot. ..."

Thinking in MYFACES-3660, this fact becomes more evident. I think we should not wait to 2.2 and instead implement this is 2.1.x/2.0.x branches because it will improve the stability of the component tree under dynamic addition/removal.

The suggested solution is do something like this:

j_id__v_1
j_id__v_2
j_id__v_3
j_id__v_4
....

This solution will keep ids small and will not cause any conflict with facelet created components or components that receive the ids through UniqueIdVendor/NamingContainer hierarchy:

j_id1
j_id2
j_id3
j_id4