Release based on cl/313536507.

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: I83ec7dee1a7ef6f4bdfd47482c94d03910525b7e

cpp/platform/api/submittable_executor_def.h

@@ -0,0 +1,49 @@
+// Copyright 2020 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef PLATFORM_API_SUBMITTABLE_EXECUTOR_DEF_H_
+#define PLATFORM_API_SUBMITTABLE_EXECUTOR_DEF_H_
+
+#include <functional>
+
+#include "platform/api/executor.h"
+#include "platform/api/future.h"
+#include "platform/callable.h"
+#include "platform/ptr.h"
+
+namespace location {
+namespace nearby {
+
+// Main interface to be used by platform as a base class for
+// - MultiThreadExecutorWrapper
+// - SingleThreadExecutorWrapper
+// Platform must override bool submit(std::function<void()>) method.
+class SubmittableExecutor : public Executor {
+ public:
+  ~SubmittableExecutor() override = default;
+
+  template <typename T>
+  Ptr<Future<T>> submit(Ptr<Callable<T>> callable);
+
+ protected:
+  // Submit a callable (with no delay).
+  // Returns true, if callable was submitted, false otherwise.
+  // Callable is not submitted if shutdown is in progress.
+  virtual bool DoSubmit(std::function<void()> wrapped_callable) = 0;
+};
+
+}  // namespace nearby
+}  // namespace location
+
+#endif  // PLATFORM_API_SUBMITTABLE_EXECUTOR_DEF_H_