Delete callbacks after use in canned browsing data helpers.

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
diff --git a/tools/valgrind/memcheck/suppressions.txt b/tools/valgrind/memcheck/suppressions.txt
index 5929c9adf654e00146042e5512c4cff3ddd70a4e..02065e54a730f07a3e2a555a5b347e08315e4daa 100644
--- a/tools/valgrind/memcheck/suppressions.txt
+++ b/tools/valgrind/memcheck/suppressions.txt
@@ -3990,13 +3990,3 @@
    fun:_ZN24BrowserRenderProcessHost22OnExtensionAddListenerERKSs
    fun:_Z16DispatchToMethodI24BrowserRenderProcessHostMS0_FvRKSsESsEvPT_T0_RK6Tuple1IT1_E
 }
-{
-   bug_51707
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN16CookiesTreeModelC2EPN3net13CookieMonsterEP26BrowsingDataDatabaseHelperP30BrowsingDataLocalStorageHelperS6_P26BrowsingDataAppCacheHelper
-   fun:_ZN26TabSpecificContentSettings27LocalSharedObjectsContainer19GetCookiesTreeModelEv
-   fun:-[CollectedCookiesWindowController loadTreeModelFromTabContents]
-   fun:-[CollectedCookiesWindowController initWithTabContents:]
-   fun:_ZN12_GLOBAL__N_154CollectedCookiesWindowControllerTest_Construction_Test8TestBodyEv
-}