Remove ModelProvider Mojo interface

We are collapsing the ModelProvider interface into the top-level
MachineLearningService interface. ModelProvider's sole method LoadModel
becomes a method of MachineLearningService.

This reflects the corresponding Chromium OS change: crrev.com/c/1158091.
(The changes are safe to perform simultaneously as no clients call this
interface yet.)

Bug: 836095
Change-Id: Ia30be3ff176a72f2873c589ad1bc8e5c53248031
Reviewed-on: https://chromium-review.googlesource.com/1160138Reviewed-by: Michael Martis <martis@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Commit-Queue: Andrew Moylan <amoylan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#580401}

chromeos/services/machine_learning/public/cpp/service_connection.cc

@@ -21,10 +21,11 @@ ServiceConnection* ServiceConnection::GetInstance() {
   return service_connection.get();
 }
 
-void ServiceConnection::BindModelProvider(mojom::ModelProviderRequest request) {
+void ServiceConnection::LoadModel(mojom::ModelSpecPtr spec,
+                                  mojom::ModelRequest request) {
   DCHECK_CALLED_ON_VALID_SEQUENCE(sequence_checker_);
   BindMachineLearningServiceIfNeeded();
-  machine_learning_service_->GetModelProvider(std::move(request));
+  machine_learning_service_->LoadModel(std::move(spec), std::move(request));
 }
 
 void ServiceConnection::BindMachineLearningServiceIfNeeded() {

chromeos/services/machine_learning/public/cpp/service_connection.h

@@ -16,18 +16,20 @@ namespace machine_learning {
 // Encapsulates a connection to the Chrome OS ML Service daemon via its Mojo
 // interface.
 // Usage:
-//   chromeos::machine_learning::mojom::ModelProviderPtr model_provider;
+//   chromeos::machine_learning::mojom::ModelPtr model;
+//   chromeos::machine_learning::mojom::ModelSpec spec;
 //   chromeos::machine_learning::ServiceConnection::GetInstance()
-//       ->BindModelProvider(mojom::MakeRequest(&model_provider));
-//   // Use model_provider ...
+//       ->LoadModel(spec, mojom::MakeRequest(&model));
+//   // Use model ...
 // Sequencing: Must be used on a single sequence (may be created on another).
 class ServiceConnection {
  public:
   static ServiceConnection* GetInstance();
 
-  // Instruct ML daemon to bind a ModelProvider implementation to |request|.
+  // Instruct ML daemon to load the model specified in |spec|, binding a Model
+  // implementation to |request|.
   // Bootstraps the initial Mojo connection to the daemon if necessary.
-  void BindModelProvider(mojom::ModelProviderRequest request);
+  void LoadModel(mojom::ModelSpecPtr spec, mojom::ModelRequest request);
 
  private:
   friend class base::NoDestructor<ServiceConnection>;

chromeos/services/machine_learning/public/cpp/service_connection_unittest.cc

@@ -42,9 +42,10 @@ class ServiceConnectionTest : public testing::Test {
 
 // Tests that BindModelProvider runs OK (no crash) in a basic Mojo environment.
 TEST_F(ServiceConnectionTest, BindModelProvider) {
-  mojom::ModelProviderPtr model_provider;
-  ServiceConnection::GetInstance()->BindModelProvider(
-      mojo::MakeRequest(&model_provider));
+  mojom::ModelPtr model;
+  mojom::ModelSpecPtr spec = mojom::ModelSpec::New(mojom::ModelId::UNKNOWN);
+  ServiceConnection::GetInstance()->LoadModel(std::move(spec),
+                                              mojo::MakeRequest(&model));
 }
 
 }  // namespace

chromeos/services/machine_learning/public/mojom/machine_learning_service.mojom

@@ -13,12 +13,8 @@ module chromeos.machine_learning.mojom;
 
 import "chromeos/services/machine_learning/public/mojom/model.mojom";
 
-interface ModelProvider {
-  // The ModelId inside ModelSpec is used to specify the model to be loaded.
-  LoadModel(ModelSpec spec, Model& request);
-};
-
 // Top-level interface between Chromium and the ML Service daemon.
 interface MachineLearningService {
-  GetModelProvider(ModelProvider& request);
+  // The ModelId inside ModelSpec is used to specify the model to be loaded.
+  LoadModel(ModelSpec spec, Model& request);
 };