Add mus::mojom::ChannelHandle for passing IPC::ChannelHandle via mojo IPC.

components/mus/gpu/BUILD.gn

Index: components/mus/gpu/BUILD.gn
diff --git a/components/mus/gpu/BUILD.gn b/components/mus/gpu/BUILD.gn
index 0bcf1fcc813ef46a8197aa918c988755a9eac1d6..a251efac67a60cec105d14e14ef82773ac34b5d1 100644
--- a/components/mus/gpu/BUILD.gn
+++ b/components/mus/gpu/BUILD.gn
@@ -2,16 +2,54 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//mojo/public/mojo_application_manifest.gni")
+import("//testing/test.gni")
+
 source_set("gpu") {
   output_name = "mus_gpu"
 
   sources = [
     "gpu_service_mus.cc",
     "gpu_service_mus.h",
+    "gpu_type_converters.cc",
+    "gpu_type_converters.h",
   ]
 
   deps = [
+    "//components/mus/public/interfaces",
     "//gpu/ipc/common",
     "//gpu/ipc/service",
+    "//ipc",
+    "//mojo/platform_handle:platform_handle",
+  ]
+}
+
+group("tests") {
+  testonly = true
+  deps = [
+    ":mus_gpu_unittests",
+  ]
+}
+
+test("mus_gpu_unittests") {
+  sources = [
+    "gpu_type_converters_unittest.cc",
+  ]
+
+  deps = [
+    ":gpu",
+    "//base",
+    "//ipc",
+    "//services/shell/public/cpp/test:run_all_shelltests",
+    "//testing/gtest",
   ]
+
+  data_deps = [
+    ":mus_gpu_unittests_app_manifest",
+  ]
+}
+
+mojo_application_manifest("mus_gpu_unittests_app_manifest") {
+  application_name = "mus_gpu_unittests_app"
+  source = "mus_gpu_unittests_app_manifest.json"
 }