Leaks found in PrefValueStoreTest tests

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 # running overnight and removing outdated bugs/suppressions.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 3880 matching lines @@
    fun:_ZN15DictionaryValue23SetWithoutPathExpansionERKSsP5Value
    fun:_ZN15DictionaryValue3SetERKSsP5Value
    fun:_ZN15DictionaryValue3SetERKSbIwSt11char_traitsIwESaIwEEP5Value
    fun:_ZN8chromeos24UserCrosSettingsProvider3SetERKSbIwSt11char_traitsIwESaIwEEP5Value
    fun:_ZN8chromeos24UserCrosSettingsProviderC1Ev
    fun:_ZN8chromeos12CrosSettingsC1Ev
    fun:_ZN22DefaultSingletonTraitsIN8chromeos12CrosSettingsEE3NewEv
    fun:_ZN9SingletonIN8chromeos12CrosSettingsE22DefaultSingletonTraitsIS1_ES1_E3getEv
    fun:_ZN8chromeos12CrosSettings3GetEv
 }
+{
+   bug_51176_a
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN51PrefValueStoreTest_TestConcurrentPolicyRefresh_Test8TestBodyEv
+}
+{
+   bug_51176_b
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN41PrefValueStoreTest_TestPolicyRefresh_Test8TestBodyEv
+}
+{
+   bug_51176_c
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN56PrefValueStoreTest_TestRefreshPolicyPrefsCompletion_Test8TestBodyEv
+}