Support valgrinding layout tests.

Support valgrinding layout tests.

Also suppress several common memory leak reports; 
http://crbug.com/9450
http://crbug.com/9458
http://crbug.com/9475
http://crbug.com/9503


Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=12776

[dank, 2009-03-27 20:26:39]

The -n option kind of replaces the layout_all test.

Defaults to running 20 tests at a time instead of 120;
we can raise that once we're more comfortable.

[Erik does not do reviews, 2009-03-30 04:04:47]

http://codereview.chromium.org/55034/diff/22/25
File tools/valgrind/chrome_tests.py (right):

http://codereview.chromium.org/55034/diff/22/25#newcode320
Line 320: parser.add_option("-n", "--num_tests", default=20, type="int",
This number seems pretty small.  Put a comment here with an estimate of how long
this takes, and the TODO that you intend to raise it.  Also, perhaps there
should be a value here that specifies running all?

http://codereview.chromium.org/55034/diff/22/24
File tools/valgrind/valgrind_analyze.py (right):

http://codereview.chromium.org/55034/diff/22/24#newcode199
Line 199: time.sleep(1)
maybe we should have a timeout?  if valgrind hangs or crashes, this looks like
it will wait forever.

http://codereview.chromium.org/55034/diff/22/24#newcode204
Line 204: if (show_all_leaks or getTextOf(raw_error, "kind") !=
"Leak_PossiblyLost"):
old code nit: 80 cols

http://codereview.chromium.org/55034/diff/22/23
File webkit/tools/layout_tests/layout_package/test_shell_thread.py (right):

http://codereview.chromium.org/55034/diff/22/23#newcode106
Line 106: wrapper = os.environ["BROWSER_WRAPPER"]
This should have a comment explaining it and how it's supposed to be used.  In
fact, I didn't see it used in chrome_tests.py as I expected.

[dank, 2009-03-30 15:56:08]

OK, I think I've addressed all issues.
(Although perhaps I should mention somewhere that 
valgrind_test.py --indirect is what sets BROWSER_WRAPPER.)

[Erik does not do reviews, 2009-03-30 16:22:48]

LGTM

http://codereview.chromium.org/55034/diff/1022/2019
File tools/valgrind/chrome_tests.py (right):

http://codereview.chromium.org/55034/diff/1022/2019#newcode218
Line 218: # If a text file is given as argument, it is used as the list of
tests.
clarify this comment to refer explicitly to command-line args rather than args
to this function.

http://codereview.chromium.org/55034/diff/1022/2019#newcode337
Line 337: help="for layout tests: number of subtests per run.  0 for all.")
80 columns

http://codereview.chromium.org/55034/diff/1022/2018
File tools/valgrind/valgrind_analyze.py (right):

http://codereview.chromium.org/55034/diff/1022/2018#newcode202
Line 202: if tries == ntries-1:
space around operator