unit_tests MetricsLogManagerTest.StoreStagedLogTypes failing with _free_dbg_lock crash

_From [bruen...@google.com](https://code.google.com/u/109494838902877177630/) on August 21, 2012 22:45:29_

toward the end of a full unit_tests component build run:

[ RUN ] MetricsLogManagerTest.StoreStagedLogTypes
Backtrace:
_free_dbg_nolock [0x687D799F+1023]
_free_dbg [0x687D7560+80]
free [0x687D9C80+16]
xmlListDelete [0x039612F3+35](d:derekchromiumsrcthird_partylibxmlsrclist.c:339)
xmlFreeTextWriter [0x038EB3D9+57](d:derekchromiumsrcthird_partylibxmlsrcxmlwriter.c:484)
MetricsLogBase::XmlWrapper::FreeDocWriter [0x0280D4BC+28](d:derekchromiumsrcchromecommonmetricsmetrics_log_base.cc:127)
MetricsLogBase::XmlWrapper::~XmlWrapper [0x0280D46F+15](d:derekchromiumsrcchromecommonmetricsmetrics_log_base.cc:119)
MetricsLogBase::XmlWrapper::`scalar deleting destructor' [0x0280D43F+15]
MetricsLogBase::~MetricsLogBase [0x0280D38B+283] (d:\derek\chromium\src\chrome\common\metrics\metrics_log_base.cc:181)
MetricsLogBase::`scalar deleting destructor' [0x0280D24F+15]
scoped_ptr::reset [0x0280C365+53](d:derekchromiumsrcbasememoryscoped_ptr.h:189)
MetricsLogManager::FinishCurrentLog [0x0280AC1A+490](d:derekchromiumsrcchromecommonmetricsmetrics_log_manager.cc:68)
MetricsLogManagerTest_StoreStagedLogTypes_Test::TestBody [0x0244703E+1406](d:derekchromiumsrcchromecommonmetricsmetrics_log_manager_unittest.cc:256)
testing::internal::HandleExceptionsInMethodIfSupportedtesting::Test,void [0x037EABF2+290](d:derekchromiumsrctestinggtestsrcgtest.cc:2128)
testing::Test::Run [0x037DE617+135](d:derekchromiumsrctestinggtestsrcgtest.cc:2143)
testing::TestInfo::Run [0x037DEDDD+173](d:derekchromiumsrctestinggtestsrcgtest.cc:2323)
testing::TestCase::Run [0x037DF3EF+191](d:derekchromiumsrctestinggtestsrcgtest.cc:2427)
testing::internal::UnitTestImpl::RunAllTests [0x037E434E+606](d:derekchromiumsrctestinggtestsrcgtest.cc:4250)
testing::internal::HandleExceptionsInMethodIfSupportedtesting::internal::UnitTestImpl,bool [0x037EB2FA+298](d:derekchromiumsrctestinggtestsrcgtest.cc:2128)
testing::UnitTest::Run [0x037E3326+150](d:derekchromiumsrctestinggtestsrcgtest.cc:3884)
base:: TestSuite ::Run [0x04117F65+197](d:derekchromiumsrcbasetesttest_suite.cc:199)
content::UnitTestTestSuite::Run [0x0426A506+22](d:derekchromiumsrccontentpublictestunittest_test_suite.cc:46)
main [0x0411954C+140](d:derekchromiumsrcchrometestbaserun_all_unittests.cc:9)
__tmainCRTStartup [0x03FFAAAF+447](f:ddvctoolscrt_bldself_x86crtsrccrtexe.c:555)
mainCRTStartup [0x03FFA8DF+15](f:ddvctoolscrt_bldself_x86crtsrccrtexe.c:371)
BaseThreadInitThunk [0x75B2339A+14]
__RtlUserThreadStart [0x77AE9EF2+112]
_RtlUserThreadStart [0x77AE9EC5+27]

~~Dr.M~~
~~Dr.M~~ NO ERRORS FOUND:
~~Dr.M~~ 0 unique, 0 total unaddressable access(es)
~~Dr.M~~ 0 unique, 0 total invalid heap argument(s)
~~Dr.M~~ 0 unique, 0 total warning(s)
~~Dr.M~~ ERRORS IGNORED:
~~Dr.M~~ 23 user-suppressed, 0 default-suppressed error(s)
~~Dr.M~~ Details: D:\derek\drmemory\git\build_x86_dbg/logs/DrMemory-unit_tests.exe.6416.000/results.txt
Command terminated by signal 11
0.00user 0.00system 1:58:09elapsed 0%CPU (0avgtext+0avgdata 204544maxresident)k

_Original issue: http://code.google.com/p/drmemory/issues/detail?id=980_