Mojo: MultiprocessTestHelper: Allow {ASSERT,EXPECT}_...() to be used in child.

mojo/common/test/multiprocess_test_helper.cc

Index: mojo/common/test/multiprocess_test_helper.cc
diff --git a/mojo/common/test/multiprocess_test_helper.cc b/mojo/common/test/multiprocess_test_helper.cc
index 90f7250578b7f3f8267954219ac19242aeb67d0e..a59a25b58412016a283388d8b0f95bf7074c8526 100644
--- a/mojo/common/test/multiprocess_test_helper.cc
+++ b/mojo/common/test/multiprocess_test_helper.cc
@@ -66,6 +66,10 @@ int MultiprocessTestHelper::WaitForChildShutdown() {
   return rv;
 }
 
+bool MultiprocessTestHelper::WaitForChildTestShutdown() {
+  return WaitForChildShutdown() == 0;
+}
+
 // static
 void MultiprocessTestHelper::ChildSetup() {
   CHECK(CommandLine::InitializedForCurrentProcess());