[mojo-edk] Stop using the sync broker on OS X

The sync broker is only needed for sandboxed shared
buffer allocation on POSIX, but it's not needed for
Mach shared buffers.

This stops using the broker on OS X.

BUG=591742,590979

Review URL: https://codereview.chromium.org/1809363002

Cr-Commit-Position: refs/heads/master@{#381908}


CrOS-Libchrome-Original-Commit: 018a4e46c477ada7307ed5c7dad7eb58b7da75b5
diff --git a/mojo/edk/system/node_controller.cc b/mojo/edk/system/node_controller.cc
index 30b331f..698238d 100644
--- a/mojo/edk/system/node_controller.cc
+++ b/mojo/edk/system/node_controller.cc
@@ -140,7 +140,7 @@
 
 void NodeController::ConnectToParent(ScopedPlatformHandle platform_handle) {
 // TODO(amistry): Consider the need for a broker on Windows.
-#if defined(OS_POSIX)
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
   // On posix, use the bootstrap channel for the broker and receive the node's
   // channel synchronously as the first message from the broker.
   broker_.reset(new Broker(std::move(platform_handle)));
@@ -231,7 +231,6 @@
 
 scoped_refptr<PlatformSharedBuffer> NodeController::CreateSharedBuffer(
     size_t num_bytes) {
-  // TODO(amistry): Fix sync broker and re-enable on OSX.
 #if defined(OS_POSIX) && !defined(OS_MACOSX)
   // Shared buffer creation failure is fatal, so always use the broker when we
   // have one. This does mean that a non-root process that has children will use
@@ -258,7 +257,7 @@
     ScopedPlatformHandle platform_handle) {
   DCHECK(io_task_runner_->RunsTasksOnCurrentThread());
 
-#if defined(OS_POSIX)
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
   PlatformChannelPair node_channel;
   // BrokerHost owns itself.
   BrokerHost* broker_host = new BrokerHost(std::move(platform_handle));
diff --git a/mojo/edk/system/node_controller.h b/mojo/edk/system/node_controller.h
index 34c2644..c177f8f 100644
--- a/mojo/edk/system/node_controller.h
+++ b/mojo/edk/system/node_controller.h
@@ -266,8 +266,8 @@
   // Must only be accessed from the IO thread.
   bool destroy_on_io_thread_shutdown_ = false;
 
-#if defined(OS_POSIX)
-  // Broker for sync shared buffer creation (posix-only) in children.
+#if defined(OS_POSIX) && !defined(OS_MACOSX)
+  // Broker for sync shared buffer creation (non-Mac posix-only) in children.
   scoped_ptr<Broker> broker_;
 #endif