Move hardware and boot_control implementation to libupdate_engine.

The implementations of the BootControlInterface and HardwareInterface
are specific to the platform and use case. The delta_generator uses the
DeltaPerformer in the libpayload_consumer to apply a payload to a set
of partitions defined as local files, for example.

This patch move the platform implementations, not available when
building for the host back to the libupdate_engine.

Bug: 24619596
TEST=mma

Change-Id: I16ab06c2e53dfd046e693bdb7310ec26a2d69054
diff --git a/boot_control_android.h b/boot_control_android.h
new file mode 100644
index 0000000..a5a6255
--- /dev/null
+++ b/boot_control_android.h
@@ -0,0 +1,61 @@
+//
+// Copyright (C) 2015 The Android Open Source Project
+//
+// 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
+//
+//      http://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 UPDATE_ENGINE_BOOT_CONTROL_ANDROID_H_
+#define UPDATE_ENGINE_BOOT_CONTROL_ANDROID_H_
+
+#include <string>
+
+#include <hardware/boot_control.h>
+#include <hardware/hardware.h>
+
+#include "update_engine/common/boot_control.h"
+
+namespace chromeos_update_engine {
+
+// The Android implementation of the BootControlInterface. This implementation
+// uses the libhardware's boot_control HAL to access the bootloader.
+class BootControlAndroid : public BootControlInterface {
+ public:
+  BootControlAndroid() = default;
+  ~BootControlAndroid() = default;
+
+  // Load boot_control HAL implementation using libhardware and
+  // initializes it. Returns false if an error occurred.
+  bool Init();
+
+  // BootControlInterface overrides.
+  unsigned int GetNumSlots() const override;
+  BootControlInterface::Slot GetCurrentSlot() const override;
+  bool GetPartitionDevice(const std::string& partition_name,
+                          BootControlInterface::Slot slot,
+                          std::string* device) const override;
+  bool IsSlotBootable(BootControlInterface::Slot slot) const override;
+  bool MarkSlotUnbootable(BootControlInterface::Slot slot) override;
+  bool SetActiveBootSlot(BootControlInterface::Slot slot) override;
+  bool MarkBootSuccessfulAsync(base::Callback<void(bool)> callback) override;
+
+ private:
+  // NOTE: There is no way to release/unload HAL implementations so
+  // this is essentially leaked on object destruction.
+  boot_control_module_t* module_;
+
+  DISALLOW_COPY_AND_ASSIGN(BootControlAndroid);
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_BOOT_CONTROL_ANDROID_H_