ml: Add mojo API of TextClassifier/Annotator.

This CL implements the mojo API of text classifier.

BUG=chromium:1020419
TEST=pass the existing unit tests.
TEST=on device (eve), 1+2=3 works.
TEST=on device (eve), Annotate() and SuggestSelection() work.

Change-Id: Iadfe5747f3b2d1f8c8a8d9f0b975e2e8cda50726
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform2/+/1951350
Tested-by: Honglin Yu <honglinyu@chromium.org>
Commit-Queue: Honglin Yu <honglinyu@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Andrew Moylan <amoylan@chromium.org>
diff --git a/ml/text_classifier_impl.h b/ml/text_classifier_impl.h
new file mode 100644
index 0000000..1dafbb0
--- /dev/null
+++ b/ml/text_classifier_impl.h
@@ -0,0 +1,65 @@
+// Copyright 2020 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef ML_TEXT_CLASSIFIER_IMPL_H_
+#define ML_TEXT_CLASSIFIER_IMPL_H_
+
+#include <list>
+#include <map>
+#include <memory>
+#include <string>
+
+#include <annotator/annotator.h>
+#include <base/macros.h>
+#include <mojo/public/cpp/bindings/binding.h>
+#include <tensorflow/lite/model.h>
+#include <utils/memory/mmap.h>
+
+#include "ml/graph_executor_impl.h"
+#include "ml/mojom/model.mojom.h"
+#include "ml/mojom/text_classifier.mojom.h"
+
+namespace ml {
+
+class TextClassifierImpl
+    : public chromeos::machine_learning::mojom::TextClassifier {
+ public:
+  // Interface to create new |TextClassifierImpl| object. This function will
+  // automatically achieve strong binding.The model object will be deleted when
+  // the corresponding mojo connection meets error.
+  // Will return false if it fails to create the annotator object, otherwise
+  // return true.
+  static bool Create(
+      std::unique_ptr<libtextclassifier3::ScopedMmap>* mmap,
+      chromeos::machine_learning::mojom::TextClassifierRequest request);
+
+ private:
+  // A private constructor, call |TextClassifierImpl::Create| to create new
+  // objects.
+  explicit TextClassifierImpl(
+      std::unique_ptr<libtextclassifier3::ScopedMmap>* mmap,
+      chromeos::machine_learning::mojom::TextClassifierRequest request);
+
+  void SetConnectionErrorHandler(base::Closure connection_error_handler);
+
+  // chromeos::machine_learning::mojom::TextClassifier:
+  void Annotate(
+      chromeos::machine_learning::mojom::TextAnnotationRequestPtr request,
+      AnnotateCallback callback) override;
+
+  // chromeos::machine_learning::mojom::TextClassifier:
+  void SuggestSelection(
+      chromeos::machine_learning::mojom::TextSuggestSelectionRequestPtr request,
+      SuggestSelectionCallback callback) override;
+
+  std::unique_ptr<libtextclassifier3::Annotator> annotator_;
+
+  mojo::Binding<chromeos::machine_learning::mojom::TextClassifier> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(TextClassifierImpl);
+};
+
+}  // namespace ml
+
+#endif  // ML_TEXT_CLASSIFIER_IMPL_H_