Flush SequenceWorkerPool tasks after each unit test.

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
===================================================================
--- tools/valgrind/memcheck/suppressions.txt	(revision 174464)
+++ tools/valgrind/memcheck/suppressions.txt	(working copy)
@@ -6282,45 +6282,6 @@
    fun:_ZN7WebCore11RenderLayer10paintLayerEPNS_15GraphicsContextERKNS0_17LayerPaintingInfoEj
 }
 {
-   bug_166470
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN4base4BindIMN11dom_storage17DomStorageContextEFvRK4GURLE13scoped_refptrIS2_ES3_EENS_8CallbackINS_8internal9BindStateINSB_13FunctorTraitsIT_E12RunnableTypeENSF_7RunTypeEFvNSB_19CallbackParamTraitsIT0_E11StorageTypeENSI_IT1_E11StorageTypeEEE14UnboundRunTypeEEESE_RKSJ_RKSM_
-   fun:_ZN7content21DOMStorageContextImpl18DeleteLocalStorageERK4GURL
-   fun:_ZN7content20StoragePartitionImpl23AsyncClearDataForOriginERK4GURLPN3net23URLRequestContextGetterE
-   fun:_ZN10extensions11DataDeleter13StartDeletingEP7ProfileRKSsRK4GURL
-   fun:_ZN16ExtensionService18UninstallExtensionESsbPSbItN4base20string16_char_traitsESaItEE
-}
-{
-   bug_166470b
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN9__gnu_cxx13new_allocatorI8FilePathE8allocateEmPKv
-   fun:_ZNSt12_Vector_baseI8FilePathSaIS0_EE11_M_allocateEm
-   fun:_ZNSt6vectorI8FilePathSaIS0_EE13_M_insert_auxEN9__gnu_cxx17__normal_iteratorIPS0_S2_EERKS0_
-   fun:_ZNSt6vectorI8FilePathSaIS0_EE9push_backERKS0_
-   fun:_ZN9file_util15CreateDirectoryERK8FilePath
-   fun:_ZN11dom_storage17DomStorageContext19GetStorageNamespaceEl
-   fun:_ZN11dom_storage17DomStorageContext18DeleteLocalStorageERK4GURL
-}
-{
-   bug_166470c
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN11dom_storage19DomStorageNamespace24DeleteLocalStorageOriginERK4GURL
-   fun:_ZN11dom_storage17DomStorageContext18DeleteLocalStorageERK4GURL
-}
-{
-   bug_166470d
-   Memcheck:Leak
-   ...
-   fun:_ZN7fileapi26GetOriginIdentifierFromURLERK4GURL
-   fun:_ZN11dom_storage14DomStorageArea26DatabaseFileNameFromOriginERK4GURL
-   fun:_ZN11dom_storage14DomStorageAreaC1ERK4GURLRK8FilePathPNS_20DomStorageTaskRunnerE
-   fun:_ZN11dom_storage19DomStorageNamespace24DeleteLocalStorageOriginERK4GURL
-   fun:_ZN11dom_storage17DomStorageContext18DeleteLocalStorageERK4GURL
-}
-{
    bug_166584
    Memcheck:Uninitialized
    fun:_ZN7testing8internal11CmpHelperEQIjjEENS_15AssertionResultEPKcS4_RKT_RKT0_