Always record all the slots of descriptor arrays to avoid crashes due to

Always record all the slots of descriptor arrays to avoid crashes due to
installing descriptors into the descriptor array before the descriptor array is
installed into the map.

This bug would be caused by, eg, appending a descriptor to an existing
descriptor array in ShareDescriptor, before installed the descriptor
array into the new map. If a GC occurs between installing the descriptor
and installing the descriptor array, the pointer to an evacuated key or
value will not be updated in the descriptor array.

BUG=

[Toon Verwaest, 2014-01-21 17:34:12]

PTAL

[Michael Starzinger, 2014-01-21 18:07:41]

LGTM if comments are addressed.

For the record, this breaks nice abstractions in the StaticMarkingVisitor and my
heart bleeds a little looking at this change.

https://codereview.chromium.org/144003007/diff/40001/src/objects-visiting-inl.h
File src/objects-visiting-inl.h (right):

https://codereview.chromium.org/144003007/diff/40001/src/objects-visiting-inl...
src/objects-visiting-inl.h:632: 
nit: Please drop the empty newline. The comment above shouldn't be separated
from the block of code below.

https://codereview.chromium.org/144003007/diff/40001/src/objects-visiting-inl...
src/objects-visiting-inl.h:648: StaticVisitor::VisitPointers(heap,
Can we move the visiting of the header slots to before we record the entry
slots? Then the memory is accessed sequentially. Also it is easier to read.

https://codereview.chromium.org/144003007/diff/40001/src/objects-visiting-inl...
src/objects-visiting-inl.h:655: StaticVisitor::VisitPointers(heap,
The call to VisitPointers here is obsolete.