Treat empty directory properly in skimage.

Treat empty directory properly in skimage.

Instead of treating an empty directory as a file that failed to
decode, treat it as an empty directory.

Add self tests to check for this.

Builds upon from https://codereview.chromium.org/17294006,
which was reverted.

R=epoger@google.com

Committed: https://code.google.com/p/skia/source/detail?r=9730

[scroggo, 2013-06-19 20:05:20]

Patch set 1 is identical to https://codereview.chromium.org/16866010

[scroggo, 2013-06-19 20:10:45]

https://codereview.chromium.org/17101029/diff/3001/tools/skimage_main.cpp
File tools/skimage_main.cpp (right):

https://codereview.chromium.org/17101029/diff/3001/tools/skimage_main.cpp#new...
tools/skimage_main.cpp:508: if (sk_isdir(readPath)) {
Patch set 2 asks the filesystem whether the path is a folder. If so, it treats
it like a folder. If it's not a folder, it is only decoded if the file exists.

[scroggo, 2013-06-19 20:27:35]

https://codereview.chromium.org/17101029/diff/10001/tools/tests/skimage_self_...
File tools/tests/skimage_self_test.py (right):

https://codereview.chromium.org/17101029/diff/10001/tools/tests/skimage_self_...
tools/tests/skimage_self_test.py:58: if not os.path.exists(expectations_dir):
Patch set 3 creates the output directories if they are not already there.

[scroggo, 2013-06-19 20:34:16]

Ready for review at patch set 4.

https://codereview.chromium.org/17101029/diff/19001/tools/tests/skimage_self_...
File tools/tests/skimage_self_test.py (right):

https://codereview.chromium.org/17101029/diff/19001/tools/tests/skimage_self_...
tools/tests/skimage_self_test.py:55: expectations_path = os.path.join(file_dir,
"skimage", "output-actual",
Patch set 4 reverts the changes in patch set 3.

Instead of creating the folders if they do not exist, set 4 adds the folders
using README files.

I don't know which is better, but the README solution is used elsewhere by the
self tests, so at least this method is consistent.

(Note that the folder for output-actual/create-expectations was checked in via
SVN, and I cannot check in an empty folder from my git checkout.)

[epoger, 2013-06-21 18:01:54]

lgtm

[scroggo, 2013-06-21 19:12:54]

Committed patchset #4 manually as r9730 (presubmit successful).