[mojo-edk] Add support for transferring mach ports.

mojo/edk/test/mojo_test_base.cc

Index: mojo/edk/test/mojo_test_base.cc
diff --git a/mojo/edk/test/mojo_test_base.cc b/mojo/edk/test/mojo_test_base.cc
index 7ec067aeae6742fe27c8f3ee33341536270d99bf..4b044f6334c9f0c1709738516e07c1b1c39f1e82 100644
--- a/mojo/edk/test/mojo_test_base.cc
+++ b/mojo/edk/test/mojo_test_base.cc
@@ -13,11 +13,29 @@
 #include "mojo/public/c/system/functions.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+#include "base/mac/mach_port_broker.h"
+#endif
+
 namespace mojo {
 namespace edk {
 namespace test {
 
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+namespace {
+base::MachPortBroker* g_mach_broker = nullptr;
+}
+#endif
+
 MojoTestBase::MojoTestBase() {
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+  if (!g_mach_broker) {
+    g_mach_broker = new base::MachPortBroker("mojo_test");
+    CHECK(g_mach_broker->Init());
+    SetMachPortProvider(g_mach_broker);
+  }
+#endif
 }
 
 MojoTestBase::~MojoTestBase() {}
@@ -31,12 +49,22 @@ MojoTestBase::ClientController& MojoTestBase::StartClient(
 
 MojoTestBase::ClientController::ClientController(const std::string& client_name,
                                                  MojoTestBase* test)
-    : test_(test)
+    : test_(test) {
 #if !defined(OS_IOS)
-      ,
-      pipe_(helper_.StartChild(client_name))
+#if defined(OS_MACOSX)
+  // This lock needs to be held while launching the child because the Mach port
+  // broker only allows task ports to be received from known child processes.
+  // However, it can only know the child process's pid after the child has
+  // launched. To prevent a race where the child process sends its task port
+  // before the pid has been registered, the lock needs to be held over both
+  // launch and child pid registration.
+  base::AutoLock lock(g_mach_broker->GetLock());
+#endif
+  pipe_ = helper_.StartChild(client_name);
+#if defined(OS_MACOSX)
+  g_mach_broker->AddPlaceholderForPid(helper_.test_child().Handle());
+#endif
 #endif
-{
 }
 
 MojoTestBase::ClientController::~ClientController() {
@@ -47,7 +75,12 @@ MojoTestBase::ClientController::~ClientController() {
 int MojoTestBase::ClientController::WaitForShutdown() {
   was_shutdown_ = true;
 #if !defined(OS_IOS)
-  return helper_.WaitForChildShutdown();
+  int retval = helper_.WaitForChildShutdown();
+#if defined(OS_MACOSX)
+  base::AutoLock lock(g_mach_broker->GetLock());
+  g_mach_broker->InvalidatePid(helper_.test_child().Handle());
+#endif
+  return retval;
 #else
   NOTREACHED();
   return 1;