Suppress WebCore NotificationCenter leak.

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 # running overnight and removing outdated bugs/suppressions.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 2633 matching lines @@
    fun:_Znw*
    fun:_ZN19TestWebViewDelegate12createWorkerEPN6WebKit8WebFrameEPNS0_15WebWorkerClientE
    fun:_ZN6WebKit19WebWorkerClientImpl24createWorkerContextProxyEPN7WebCore6WorkerE
    fun:_ZN7WebCore18WorkerContextProxy6createEPNS_6WorkerE
    fun:_ZN7WebCore6WorkerC1ERKNS_6StringEPNS_22ScriptExecutionContextERi
    fun:_ZN7WebCore6Worker6createERKNS_6StringEPNS_22ScriptExecutionContextERi
    fun:_ZN7WebCore8V8Worker19constructorCallbackERKN2v89ArgumentsE
    fun:_ZN2v88internal19HandleApiCallHelperILb1EEEPNS0_6ObjectENS0_47_GLOBAL__N_v8_src_builtins.cc_00000000_2CCEFB9216BuiltinArgumentsILNS0_21BuiltinExtraArgumentsE1EEE
    obj:*
 }
+{
+   bug_42866
+   Memcheck:Leak
+   fun:malloc
+   fun:_ZN3WTF10fastMallocEj
+   fun:_ZN3WTF13FastAllocBasenwEj
+   fun:_ZN7WebCore12Notification6createERKNS_20NotificationContentsEPNS_22ScriptExecutionContextERiPNS_21NotificationPresenterE
+   fun:_ZN7WebCore18NotificationCenter18createNotificationERKNS_6StringES3_S3_Ri
+   fun:_ZN7WebCore20V8NotificationCenter26createNotificationCallbackERKN2v89ArgumentsE
+   fun:_ZN2v88internal19HandleApiCallHelperILb0EEEPNS0_6ObjectENS0_47_GLOBAL__N_v8_src_builtins.cc_00000000_2CCEFB9216BuiltinArgumentsILNS0_21BuiltinExtraArgumentsE1EEE
+   obj:*
+   obj:*
+   obj:*
+   obj:*
+   obj:*
+   fun:_ZN2v88internal6InvokeEbNS0_6HandleINS0_10JSFunctionEEENS1_INS0_6ObjectEEEiPPPS4_Pb
+}