skimage: report failure if expectation not found.

skimage: report failure if expectation not found.

If the expectation file exists, but the particular file being
decoded has no expectation, report a failure.

This is more appropriate since the intended use is that an
expectation will be created for each file. Without an expectation,
we cannot know whether the decoder has changed.

R=epoger@google.com

Committed: https://code.google.com/p/skia/source/detail?r=9122

[epoger, 2013-05-14 16:38:31]

LGTM with or without optional suggestion

https://codereview.chromium.org/15094011/diff/2001/tools/skimage_main.cpp
File tools/skimage_main.cpp (right):

https://codereview.chromium.org/15094011/diff/2001/tools/skimage_main.cpp#new...
tools/skimage_main.cpp:205: *  @return bool True if the bitmap matched the
expectation, or if there was no expectation file.
might be clearer this way:

@return bool True in any of these cases:
  - the bitmap matches the expectation
  - there is no expectation file
False in any of these cases:
  - there is an expectation file, but no expectation for this particular bitmap
  - there is an expectation for this bitmap, but it did not match
  - expectation could not be computed from the bitmap

[scroggo, 2013-05-14 17:30:01]

https://codereview.chromium.org/15094011/diff/2001/tools/skimage_main.cpp
File tools/skimage_main.cpp (right):

https://codereview.chromium.org/15094011/diff/2001/tools/skimage_main.cpp#new...
tools/skimage_main.cpp:205: *  @return bool True if the bitmap matched the
expectation, or if there was no expectation file.
On 2013/05/14 16:38:31, epoger wrote:
> might be clearer this way:
> 
> @return bool True in any of these cases:
>   - the bitmap matches the expectation
>   - there is no expectation file
> False in any of these cases:
>   - there is an expectation file, but no expectation for this particular
bitmap
>   - there is an expectation for this bitmap, but it did not match
>   - expectation could not be computed from the bitmap

Done.

[scroggo, 2013-05-14 17:30:25]

Committed patchset #3 manually as r9122 (presubmit successful).