Split payload application code into a subdirectory.

This patch splits from the main libupdate_engine code the part that
is strictly used to download and apply a payload into a new static
library, moving the code to subdirectories. The new library is divided
in two subdirectories: common/ and payload_consumer/, and should not
depend on other update_engine files outside those two subdirectories.
The main difference between those two is that the common/ tools are more
generic and not tied to the payload consumer process, but otherwise they
are both compiled together.

There are still dependencies from the new libpayload_consumer library
into the main directory files and DBus generated files. Those will be
addressed in follow up CLs.

Bug: 25197634
Test: FEATURES=test emerge-link update_engine; `mm` on Brillo.

Change-Id: Id8d0204ea573627e6e26ca9ea17b9592ca95bc23

common/hardware_interface.h

diff --git a/common/hardware_interface.h b/common/hardware_interface.h
new file mode 100644
index 0000000..17ce694
--- /dev/null
+++ b/common/hardware_interface.h
@@ -0,0 +1,81 @@
+//
+// Copyright (C) 2013 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_COMMON_HARDWARE_INTERFACE_H_
+#define UPDATE_ENGINE_COMMON_HARDWARE_INTERFACE_H_
+
+#include <string>
+#include <vector>
+
+#include <base/files/file_path.h>
+#include <base/time/time.h>
+
+namespace chromeos_update_engine {
+
+// The hardware interface allows access to the crossystem exposed properties,
+// such as the firmware version, hwid, verified boot mode.
+// These stateless functions are tied together in this interface to facilitate
+// unit testing.
+class HardwareInterface {
+ public:
+  virtual ~HardwareInterface() {}
+
+  // Returns whether this is an official build. Official build means that the
+  // server maintains and updates the build, so update_engine should run and
+  // periodically check for updates.
+  virtual bool IsOfficialBuild() const = 0;
+
+  // Returns true if the boot mode is normal or if it's unable to
+  // determine the boot mode. Returns false if the boot mode is
+  // developer. A dev-mode boot will allow the user to access developer-only
+  // features.
+  virtual bool IsNormalBootMode() const = 0;
+
+  // Returns true if the OOBE process has been completed and EULA accepted,
+  // False otherwise. If True is returned, and |out_time_of_oobe| isn't null,
+  // the time-stamp of when OOBE happened is stored at |out_time_of_oobe|.
+  virtual bool IsOOBEComplete(base::Time* out_time_of_oobe) const = 0;
+
+  // Returns the HWID or an empty string on error.
+  virtual std::string GetHardwareClass() const = 0;
+
+  // Returns the firmware version or an empty string if the system is
+  // not running chrome os firmware.
+  virtual std::string GetFirmwareVersion() const = 0;
+
+  // Returns the ec version or an empty string if the system is not
+  // running a custom chrome os ec.
+  virtual std::string GetECVersion() const = 0;
+
+  // Returns the powerwash_count from the stateful. If the file is not found
+  // or is invalid, returns -1. Brand new machines out of the factory or after
+  // recovery don't have this value set.
+  virtual int GetPowerwashCount() const = 0;
+
+  // Store in |path| the path to a non-volatile directory (persisted across
+  // reboots) available for this daemon. In case of an error, such as no
+  // directory available, returns false.
+  virtual bool GetNonVolatileDirectory(base::FilePath* path) const = 0;
+
+  // Store in |path| the path to a non-volatile directory persisted across
+  // powerwash cycles. In case of an error, such as no directory available,
+  // returns false.
+  virtual bool GetPowerwashSafeDirectory(base::FilePath* path) const = 0;
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // UPDATE_ENGINE_COMMON_HARDWARE_INTERFACE_H_