Fix another race condition on worker process shutdown that results in use-aft...

tools/valgrind/memcheck/suppressions.txt

 # There are three 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 # running overnight and removing outdated bugs/suppressions.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 948 matching lines @@
    fun:_ZN7WebCore12parseUASheetEPKcj
    fun:_ZN7WebCore22loadSimpleDefaultStyleEv
    fun:_ZN7WebCore16CSSStyleSelectorC1EPNS_8DocumentEPNS_14StyleSheetListEPNS_13CSSStyleSheetES6_PKN3WTF6VectorINS7_6RefPtrIS5_EELj0EEEbb
    fun:_ZN7WebCore8Document6attachEv
    fun:_ZN7WebCore5Frame11setDocumentEN3WTF10PassRefPtrINS_8DocumentEEE
    fun:_ZN7WebCore11FrameLoader5beginERKNS_4KURLEbPNS_14SecurityOriginE
    fun:_ZN7WebCore11FrameLoader4initEv
    fun:_ZN7WebCore5Frame4initEv
 }
 {
-   bug_23018_a
-   Memcheck:Addr4
-   fun:_ZN12_GLOBAL__N_115KillProcessTask3RunEv
-   fun:_ZN11MessageLoop7RunTaskEP4Task
-   fun:_ZN11MessageLoop21DeferOrRunPendingTaskERKNS_11PendingTaskE
-   fun:_ZN11MessageLoop13DoDelayedWorkEPN4base4TimeE
-}
-{
-   # This is the same callstack as above, but for whatever reason the signature
-   # of the top line, KillProcessTask::Run(), is displayed differently.
-   bug_23018_b
-   Memcheck:Addr4
-   fun:_ZN122_GLOBAL__N__b_slave_chromium_rel_linux_valgrind_builder_build_src_chrome_worker_webworkerclient_proxy.cc_00000000_BBD84F3C15KillProcessTask3RunEv
-   fun:_ZN11MessageLoop7RunTaskEP4Task
-   fun:_ZN11MessageLoop21DeferOrRunPendingTaskERKNS_11PendingTaskE
-   fun:_ZN11MessageLoop13DoDelayedWorkEPN4base4TimeE
-}
-{
    bug_23151
    Memcheck:Addr4
    ...
    fun:_ZN7WebCore23V8AbstractEventListener11handleEventEPNS_5EventE
    fun:_ZN7WebCore11EventTarget18fireEventListenersEPNS_5EventE
    fun:_ZN7WebCore11EventTarget13dispatchEventEN3WTF10PassRefPtrINS_5EventEEE
    fun:_ZN7WebCore14XMLHttpRequest28callReadyStateChangeListenerEv
 }
 {
    bug_23197
@@ skipping 101 matching lines @@
    fun:_ZN10RenderView15CapturePageInfoEib
    fun:_Z16DispatchToMethodI10RenderViewMS0_FvibEibEvPT_T0_RK6Tuple2IT1_T2_E
    fun:_ZN27ScopedRunnableMethodFactoryI10RenderViewE14RunnableMethodIMS0_FvibE6Tuple2IibEE3RunEv
    fun:_ZN11MessageLoop7RunTaskEP4Task
    fun:_ZN11MessageLoop21DeferOrRunPendingTaskERKNS_11PendingTaskE
    fun:_ZN11MessageLoop13DoDelayedWorkEPN4base4TimeE
    fun:_ZN4base18MessagePumpDefault3RunEPNS_11MessagePump8DelegateE
    fun:_ZN11MessageLoop11RunInternalEv
    fun:_ZN11MessageLoop10RunHandlerEv
 }
-{
-   bug_24346
-   Memcheck:Addr4
-   fun:_ZN13WebWorkerImpl25ReportPendingActivityTaskEPN7WebCore22ScriptExecutionContextEPS_b
-   fun:_ZN7WebCore18GenericWorkerTask2IP13WebWorkerImplS2_bbE11performTaskEPNS_22ScriptExecutionContextE
-   fun:_ZN13WebWorkerImpl16InvokeTaskMethodEPv
-   fun:_ZN3WTF31dispatchFunctionsFromMainThreadEv
-   fun:_Z18DispatchToFunctionIPFvvEEvT_RK6Tuple0
-   fun:_ZN16RunnableFunctionIPFvvE6Tuple0E3RunEv
-   fun:_ZN11MessageLoop7RunTaskEP4Task
-   fun:_ZN11MessageLoop21DeferOrRunPendingTaskERKNS_11PendingTaskE
-   fun:_ZN11MessageLoop6DoWorkEv
-   fun:_ZN4base18MessagePumpDefault3RunEPNS_11MessagePump8DelegateE
-   fun:_ZN11MessageLoop11RunInternalEv
-   fun:_ZN11MessageLoop10RunHandlerEv
-}