It does not make a real sense to use constructor for implementations that act
as a trampoline; instead, we should do a constructor for the real
implementations that hide behind it.

This reverts commit 2fbb4715.
This reverts (part of) commit 58ea2712.
This reverts (part of) commit 194bdbde.
This reverts (part of) commit df002e39.
This reverts (part of) commit eb89c6f7.
This reverts (part of) commit bdeb57c2.
This reverts (part of) commit 4337a066.

Change-Id: Ibd9b1066f3b6ea215d8da9f491d5f026cd75b029