Get rid of the distinction between modifiers and expectations.

Get rid of the distinction between modifiers and expectations.

Now there are just the platform specifiers and the expectations
and they match the syntax of the expectations file, i.e.
specifiers are in the brackets before the test and
expectations are in the brackets after the tests.

In addition to cleaning up the code, this makes it so that we
don't artificially add a PASS expectation to SLOW, WONTFIX, etc. tests.
This, in turn, fixes a bug where merging two expectations line
would mark the test as flaky, e.g.:
"foo.html [ Slow ]" merged with "foo.html [ Failure ]" would 
become "foo.html [ Slow Pass Failure ]" before this patch.

R=dpranke@chromium.org

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=155028

[Dirk Pranke, 2013-07-26 23:07:28]

LGTM. A few nits ...

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
File Tools/Scripts/webkitpy/layout_tests/controllers/manager.py (right):

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
Tools/Scripts/webkitpy/layout_tests/controllers/manager.py:143: return
test_expectations.MISSING in expectations or test_expectations.NEEDS_REBASELINE
in expectations or test_expectations.NEEDS_MANUAL_REBASELINE in expectations
Nit: Maybe push this into TetsExpectationsLine.is_expected_missing() ?

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
Tools/Scripts/webkitpy/layout_tests/controllers/manager.py:146: return
test_expectations.SLOW in self._expectations.model().get_expectations(test_file)
Nit: maybe push this into TestExpectationsLine.test_is_slow() ?

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
File Tools/Scripts/webkitpy/layout_tests/models/test_expectations.py (left):

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
Tools/Scripts/webkitpy/layout_tests/models/test_expectations.py:1096: def
remove_rebaselined_tests(self, except_these_tests, filename):
I was a bit surprised that this was gone, but I guess you removed it in one of
the previous cleanups of the rebaselining commands (I see the only callers now
are in fact the unittests).

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
File Tools/Scripts/webkitpy/layout_tests/models/test_expectations.py (right):

https://codereview.chromium.org/20830003/diff/3001/Tools/Scripts/webkitpy/lay...
Tools/Scripts/webkitpy/layout_tests/models/test_expectations.py:75: # FIXME:
Rename these to *_KEYWORD as in MISSING_KEYWORD above, but make the case
studdly-caps to match the actual file contents.
"studly" ?

[ojan, 2013-07-26 23:53:44]

Committed patchset #2 manually as r155028 (presubmit successful).