Make multiple attempts to write binding files to disc

Make multiple attempts to write binding files to disc

Our dartium-win builders are currently flaky on the compile step. Sometimes
we're not able to write the generated dart bindings to disc (we get an IOError:
Permission denied).

This change makes sure we do multiple attempts for writing out the generated
files before we give up. Hopefully we can eliminate this hack as soon as we
found the root cause.

TBR=efortuna@google.com

Committed: https://code.google.com/p/dart/source/detail?r=24772

[kustermann, 2013-07-04 11:54:16]

https://codereview.chromium.org/18676003/diff/2001/tools/dom/scripts/multiemi...
File tools/dom/scripts/multiemitter.py (left):

https://codereview.chromium.org/18676003/diff/2001/tools/dom/scripts/multiemi...
tools/dom/scripts/multiemitter.py:9: import re
"re" was unused

[kustermann, 2013-07-04 11:55:28]

Committed patchset #2 manually as r24772 (presubmit successful).

[Emily Fortuna, 2013-07-08 17:00:55]

lgtm. I'll be interested to see if waiting any amount of time ever changes the
permission denied situation or if we always go through the maximum number of
tries to write.

[kustermann, 2013-07-09 15:14:31]

On 2013/07/08 17:00:55, Emily Fortuna wrote:
> lgtm. I'll be interested to see if waiting any amount of time ever changes the
> permission denied situation or if we always go through the maximum number of
> tries to write.

After I've landed this CL, I haven't seen a single compile failure due to
"permission denied". So we successfully hide this issue.

My best guess so far is something like this:
MSBuild.exe/VS/... opens the directory (in order to list the files in there) in
an exclusive mode for a short amount of time and multiemitter.py tries to write
and gets the "permission denied" error.
(The reason why this could make sense is that VisualStudio is responsible for
tracking the dependencies when building. Meaning it has to look for the
timestamps of input/output files of actions/targets ...)