Add test_image script for checking that dependencies in image are sane

Add test_image script for checking that dependencies in image are sane

[kmixter1, 2010-03-01 23:37:32]

LGTM after issues below resolved.

http://codereview.chromium.org/661239/diff/7/8
File src/scripts/check_deps (right):

http://codereview.chromium.org/661239/diff/7/8#newcode11
src/scripts/check_deps:11: SHARED_RE = re.compile(r"Shared library:
\[([^\]]+)\]")
Usually prefix these with _ if they're internal constants

http://codereview.chromium.org/661239/diff/7/8#newcode26
src/scripts/check_deps:26: self.root = root
prefix these with _ if they're internal class variables.

http://codereview.chromium.org/661239/diff/7/8#newcode27
src/scripts/check_deps:27: self.errors = False
Not used.

http://codereview.chromium.org/661239/diff/7/8#newcode44
src/scripts/check_deps:44: for lib in os.listdir(path):
So you're assuming any file in one of the libcache directories is a shared
object.  Might be worth a comment to that effect.

http://codereview.chromium.org/661239/diff/7/8#newcode47
src/scripts/check_deps:47: def _ReadDependencies(self, binary, libcache):
So reading the dependencies of a binary also updates the libcache for library
rpaths.  Please add comment as that's not obvious from the name of the function
- also comment that you'll want to operate on a copy of the system libraries.

http://codereview.chromium.org/661239/diff/7/8#newcode52
src/scripts/check_deps:52: for line in os.popen("readelf -d '%s' 2>/dev/null" %
binary):
Do you need to explicitly close the os.popen pipe?  I'm not sure but leaking a
resource on every call could cause trouble in the future if we add more execs to
check.

http://codereview.chromium.org/661239/diff/7/8#newcode94
src/scripts/check_deps:94: 
please remove extra line

http://codereview.chromium.org/661239/diff/7/8#newcode100
src/scripts/check_deps:100: if sys.argv[1] == "-v":
one more parameter and you'll want to use getopt, but for now it's ok.

[davidjames, 2010-03-02 23:54:26]

I fixed the issues above and checked it in. I also cleaned up _ReadDependencies
so that it doesn't have the confusing behavior of modifying arguments and
instead returns the necessary stuff.

After committing, I noticed I misread two of your style nits, so I filed
issue661415 to fix that.