A speculative fix for TSAN and HeapCheck failures in InMemoryURLIndexCacheTest.

tools/valgrind/tsan/suppressions.txt

 # There are a few kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 971 matching lines @@
   fun:avcodec_open2
   fun:avformat_find_stream_info
   fun:media::FFmpegConfigHelper::SetupStreamConfigs
   fun:media::FFmpegConfigHelper::Parse
   fun:media::WebMStreamParser::ParseInfoAndTracks
   fun:media::WebMStreamParser::Parse
   fun:media::ChunkDemuxer::AppendData
   fun:media::MockMediaSource::AppendAtTime
   fun:media::PipelineIntegrationTest_MediaSource_ConfigChange_WebM_Test::TestBody
 }
-{
-  bug_146322_a
-  ThreadSanitizer:Race
-  ...
-  fun:sql::Connection::StatementRefCreated
-  fun:sql::Connection::StatementRef::StatementRef
-  fun:sql::Connection::GetUniqueStatement
-  ...
-  fun:history::*
-}
-{
-  bug_146322_b
-  ThreadSanitizer:Race
-  ...
-  fun:sql::Connection::StatementRefDeleted
-  fun:sql::Connection::StatementRef::~StatementRef
-  fun:base::RefCounted::Release
-  fun:scoped_refptr::~scoped_refptr
-  fun:sql::Statement::~Statement
-  fun:history::InMemoryURLIndexTest::SetUp
-}