Bug 1069695 - Use --trace-children=yes in |mach valgrind-test|. r=jseward.

--HG--
extra : rebase_source : 3514fc02297fea921c13df7c8c02ab07c54616ab

build/valgrind/mach_commands.py

@@ -108,7 +108,8 @@ class MachCommands(MachCommandBase):
                 '--num-callers=36',
                 '--leak-check=full',
                 '--show-possibly-lost=no',
-                '--track-origins=yes'
+                '--track-origins=yes',
+                '--trace-children=yes',
             ]
 
             for s in suppressions: