Use ChannelMojo between app shims and the browser process.

chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm

Index: chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm
diff --git a/chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm b/chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm
index d5808a4625640258246a365042d1eb87752beea3..33f94c58b231b5270b4c476086b3229e5aa10e2e 100644
--- a/chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm
+++ b/chrome/browser/apps/app_shim/app_shim_host_manager_browsertest_mac.mm
@@ -21,9 +21,12 @@
 #include "chrome/test/base/in_process_browser_test.h"
 #include "components/version_info/version_info.h"
 #include "content/public/test/test_utils.h"
+#include "ipc/ipc_channel_mojo.h"
 #include "ipc/ipc_channel_proxy.h"
 #include "ipc/ipc_listener.h"
 #include "ipc/ipc_message.h"
+#include "mojo/edk/embedder/embedder.h"
+#include "mojo/edk/embedder/named_platform_handle_utils.h"
 
 namespace {
 
@@ -65,9 +68,12 @@ TestShimClient::TestShimClient() : io_thread_("TestShimClientIO") {
   CHECK(base::ReadSymbolicLink(symlink_path, &socket_path));
   app_mode::VerifySocketPermissions(socket_path);
 
-  IPC::ChannelHandle handle(socket_path.value());
-  channel_ = IPC::ChannelProxy::Create(handle, IPC::Channel::MODE_NAMED_CLIENT,
-                                       this, io_thread_.task_runner().get());
+  channel_ = IPC::ChannelProxy::Create(
+      IPC::ChannelMojo::CreateClientFactory(
+          mojo::edk::ConnectToPeerProcess(mojo::edk::CreateClientHandle(
+              mojo::edk::NamedPlatformHandle(socket_path.value()))),
+          io_thread_.task_runner().get()),
+      this, io_thread_.task_runner().get());
 }
 
 TestShimClient::~TestShimClient() {}