Make mallinfo count all arenas.

Bug: 15455302
Change-Id: Ia6efb821a0c333de3e7cb94410932dc896ad47e3
Remove stray include.

I left an unneccessary include, so removing.

Bug: 15455302
Change-Id: Ic9fd9409f305ce84ece3c750f60e313296efad28
Decrease default chunk size from 4MB to 1MB.

This will lower the amount of wasted memory on processes that do not
allocate a lot of memory.

Change-Id: If96b79a9c0c1627e85d8f84b24baf880a0440745
Merge "Decrease default chunk size from 4MB to 1MB."