Impl mus::mojom::GpuService to enable using Chrome IPC version gpu CmdBuf in mus

components/mus/public/cpp/BUILD.gn

Index: components/mus/public/cpp/BUILD.gn
diff --git a/components/mus/public/cpp/BUILD.gn b/components/mus/public/cpp/BUILD.gn
index 8ffa1890a2bea0cee040882c4fcc149df0d41c8d..1b9f1fe838dd0ff2ffd99912dbd42417a5cd63b3 100644
--- a/components/mus/public/cpp/BUILD.gn
+++ b/components/mus/public/cpp/BUILD.gn
@@ -2,15 +2,26 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-source_set("cpp") {
+component("cpp") {
+  output_name = "mus_public_cpp"
+  deps = [
+    ":sources",
+  ]
+}
+
+source_set("sources") {
   sources = [
     "context_provider.h",
     "gles2_context.h",
+    "gpu_service.h",
     "input_event_handler.h",
     "lib/command_buffer_client_impl.cc",
     "lib/command_buffer_client_impl.h",
     "lib/context_provider.cc",
     "lib/gles2_context.cc",
+    "lib/gpu_memory_buffer_manager_mus.cc",
+    "lib/gpu_memory_buffer_manager_mus.h",
+    "lib/gpu_service.cc",
     "lib/in_flight_change.cc",
     "lib/in_flight_change.h",
     "lib/output_surface.cc",
@@ -25,6 +36,7 @@ source_set("cpp") {
     "lib/window_tree_client_impl.h",
     "lib/window_tree_delegate.cc",
     "lib/window_tree_host_factory.cc",
+    "mus_public_export",
     "output_surface.h",
     "property_type_converters.h",
     "scoped_window_ptr.h",
@@ -41,6 +53,8 @@ source_set("cpp") {
     "window_tree_host_factory.h",
   ]
 
+  defines = [ "MUS_PUBLIC_IMPLEMENTATION" ]
+
   public_deps = [
     "../interfaces",
   ]
@@ -61,6 +75,7 @@ source_set("cpp") {
     "//mojo/converters/input_events",
     "//mojo/converters/surfaces",
     "//mojo/public/c/gles2:gles2",
+    "//mojo/public/c/system:for_component",
     "//mojo/public/cpp/bindings:bindings",
     "//mojo/public/cpp/system",
     "//services/shell/public/cpp",