Suppress a leak report in mojo's HandleWrapper::Create.

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 a5bb300553d171cce47220cfa3dbf3945b329636..9d5b4ad330d50b8739c55f0c6d30dc30d2812379 100644
--- a/tools/valgrind/memcheck/suppressions.txt
+++ b/tools/valgrind/memcheck/suppressions.txt
@@ -3144,3 +3144,15 @@
    ...
    fun:_ZN4base4BindIMN7content21ChromeAppCacheServiceEFvRKNS_8FilePathEPNS1_15ResourceContextEPN3net23URLRequestContextGetterE13scoped_refptrIN7storage20SpecialStoragePolicyEEEJPS2_S3_S7_SB_IS9_ESE_EEENS_8CallbackINS_8internal22MakeUnboundRunTypeImplIT_JDpT0_EE4TypeEEESM_DpOSN_
 }
+{
+   bug_600484
+   Memcheck:Leak
+   fun:_Znw*
+   fun:_ZN4mojo3edk2js13HandleWrapper6Create*
+   fun:_ZN3gin9ConverterIN4mojo6Handle*
+   fun:_ZN3gin11ConvertToV8IN4mojo6Handle*
+   fun:_ZN3gin10ToV8TraitsIN4mojo6HandleELb0EE14TryConvertToV8*
+   fun:_ZN3gin14TryConvertToV8IN4mojo6Handle*
+   fun:_ZN3gin10Dictionary3SetIN4mojo6Handle*
+   fun:_ZN4mojo3edk2js12_GLOBAL__N_114CreateDataPipe*
+}