Account for '\0' string terminator in allocated buffers.

Account for '\0' string terminator in allocated buffers.

OS::SNPrint takes a size in bytes argument that includes the null
terminator, it returns the number of characters printed not including
the null terminator.  Unfortunately we don't have a uniform way of
writing this.

This change fixes three sites that do not account for the terminator
when writing, with the effect of dropping the last character before
the terminator.

R=srdjan@google.com
BUG=

Committed: https://code.google.com/p/dart/source/detail?r=10329

[srdjan, 2012-08-06 16:07:19]

LGTM and thanks!

https://chromiumcodereview.appspot.com/10823181/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://chromiumcodereview.appspot.com/10823181/diff/1/runtime/vm/object.cc#n...
runtime/vm/object.cc:6936: intptr_t len = 1;
Add comment: // Trailing '\0'.

[Kevin Millikin (Google), 2012-08-07 10:07:59]

https://chromiumcodereview.appspot.com/10823181/diff/1/runtime/vm/object.cc
File runtime/vm/object.cc (right):

https://chromiumcodereview.appspot.com/10823181/diff/1/runtime/vm/object.cc#n...
runtime/vm/object.cc:6936: intptr_t len = 1;
On 2012/08/06 16:07:19, srdjan wrote:
> Add comment: // Trailing '\0'.

Done.