diff --git a/fake_system_state.h b/fake_system_state.h
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--- /dev/null
+++ b/fake_system_state.h
@@ -0,0 +1,265 @@
+// Copyright (c) 2012 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_SYSTEM_STATE_H_
+#define CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_SYSTEM_STATE_H_
+
+#include <base/logging.h>
+#include <gmock/gmock.h>
+#include <policy/mock_device_policy.h>
+
+#include "metrics/metrics_library_mock.h"
+#include "update_engine/fake_clock.h"
+#include "update_engine/fake_hardware.h"
+#include "update_engine/mock_connection_manager.h"
+#include "update_engine/mock_dbus_wrapper.h"
+#include "update_engine/mock_gpio_handler.h"
+#include "update_engine/mock_p2p_manager.h"
+#include "update_engine/mock_payload_state.h"
+#include "update_engine/policy_manager/fake_policy_manager.h"
+#include "update_engine/prefs_mock.h"
+#include "update_engine/system_state.h"
+#include "update_engine/update_attempter_mock.h"
+
+namespace chromeos_update_engine {
+
+// Mock the SystemStateInterface so that we could lie that
+// OOBE is completed even when there's no such marker file, etc.
+class FakeSystemState : public SystemState {
+ public:
+  FakeSystemState();
+
+  // Base class overrides. All getters return the current implementation of
+  // various members, either the default (fake/mock) or the one set to override
+  // it by client code.
+
+  virtual inline ClockInterface* clock() override {
+    return clock_;
+  }
+
+  virtual inline void set_device_policy(
+      const policy::DevicePolicy* device_policy) override {
+    device_policy_ = device_policy;
+  }
+
+  virtual inline const policy::DevicePolicy* device_policy() override {
+    return device_policy_;
+  }
+
+  virtual inline ConnectionManager* connection_manager() override {
+    return connection_manager_;
+  }
+
+  virtual inline HardwareInterface* hardware() override {
+    return hardware_;
+  }
+
+  virtual inline MetricsLibraryInterface* metrics_lib() override {
+    return metrics_lib_;
+  }
+
+  virtual inline PrefsInterface* prefs() override {
+    return prefs_;
+  }
+
+  virtual inline PrefsInterface* powerwash_safe_prefs() override {
+    return powerwash_safe_prefs_;
+  }
+
+  virtual inline PayloadStateInterface* payload_state() override {
+    return payload_state_;
+  }
+
+  virtual inline GpioHandler* gpio_handler() override {
+    return gpio_handler_;
+  }
+
+  virtual inline UpdateAttempter* update_attempter() override {
+    return update_attempter_;
+  }
+
+  virtual inline OmahaRequestParams* request_params() override {
+    return request_params_;
+  }
+
+  virtual inline P2PManager* p2p_manager() override {
+    return p2p_manager_;
+  }
+
+  virtual inline chromeos_policy_manager::PolicyManager* policy_manager()
+      override {
+    return policy_manager_;
+  }
+
+  virtual inline bool system_rebooted() override {
+    return fake_system_rebooted_;
+  }
+
+  // Setters for the various members, can be used for overriding the default
+  // implementations. For convenience, setting to a null pointer will restore
+  // the default implementation.
+
+  inline void set_clock(ClockInterface* clock) {
+    clock_ = clock ? clock : &fake_clock_;
+  }
+
+  inline void set_connection_manager(ConnectionManager* connection_manager) {
+    connection_manager_ = (connection_manager ? connection_manager :
+                           &mock_connection_manager_);
+  }
+
+  inline void set_hardware(HardwareInterface* hardware) {
+    hardware_ = hardware ? hardware : &fake_hardware_;
+  }
+
+  inline void set_metrics_lib(MetricsLibraryInterface* metrics_lib) {
+    metrics_lib_ = metrics_lib ? metrics_lib : &mock_metrics_lib_;
+  }
+
+  inline void set_prefs(PrefsInterface* prefs) {
+    prefs_ = prefs ? prefs : &mock_prefs_;
+  }
+
+  inline void set_powerwash_safe_prefs(PrefsInterface* powerwash_safe_prefs) {
+    powerwash_safe_prefs_ = (powerwash_safe_prefs ? powerwash_safe_prefs :
+                             &mock_powerwash_safe_prefs_);
+  }
+
+  inline void set_payload_state(PayloadStateInterface *payload_state) {
+    payload_state_ = payload_state ? payload_state : &mock_payload_state_;
+  }
+
+  inline void set_gpio_handler(GpioHandler* gpio_handler) {
+    gpio_handler_ = gpio_handler ? gpio_handler : &mock_gpio_handler_;
+  }
+
+  inline void set_update_attempter(UpdateAttempter* update_attempter) {
+    update_attempter_ = (update_attempter ? update_attempter :
+                         &mock_update_attempter_);
+  }
+
+  inline void set_request_params(OmahaRequestParams* request_params) {
+    request_params_ = (request_params ? request_params :
+                       &default_request_params_);
+  }
+
+  inline void set_p2p_manager(P2PManager *p2p_manager) {
+    p2p_manager_ = p2p_manager ? p2p_manager : &mock_p2p_manager_;
+  }
+
+  inline void set_policy_manager(
+      chromeos_policy_manager::PolicyManager *policy_manager) {
+    policy_manager_ = policy_manager ? policy_manager : &fake_policy_manager_;
+  }
+
+  inline void set_system_rebooted(bool system_rebooted) {
+    fake_system_rebooted_ = system_rebooted;
+  }
+
+  // Getters for the built-in default implementations. These return the actual
+  // concrete type of each implementation. For additional safety, they will fail
+  // whenever the requested default was overridden by a different
+  // implementation.
+
+  inline FakeClock* fake_clock() {
+    CHECK(clock_ == &fake_clock_);
+    return &fake_clock_;
+  }
+
+  inline testing::NiceMock<MockConnectionManager>* mock_connection_manager() {
+    CHECK(connection_manager_ == &mock_connection_manager_);
+    return &mock_connection_manager_;
+  }
+
+  inline FakeHardware* fake_hardware() {
+    CHECK(hardware_ == &fake_hardware_);
+    return &fake_hardware_;
+  }
+
+  inline testing::NiceMock<MetricsLibraryMock>* mock_metrics_lib() {
+    CHECK(metrics_lib_ == &mock_metrics_lib_);
+    return &mock_metrics_lib_;
+  }
+
+  inline testing::NiceMock<PrefsMock> *mock_prefs() {
+    CHECK(prefs_ == &mock_prefs_);
+    return &mock_prefs_;
+  }
+
+  inline testing::NiceMock<PrefsMock> *mock_powerwash_safe_prefs() {
+    CHECK(powerwash_safe_prefs_ == &mock_powerwash_safe_prefs_);
+    return &mock_powerwash_safe_prefs_;
+  }
+
+  inline testing::NiceMock<MockPayloadState>* mock_payload_state() {
+    CHECK(payload_state_ == &mock_payload_state_);
+    return &mock_payload_state_;
+  }
+
+  inline testing::NiceMock<MockGpioHandler>* mock_gpio_handler() {
+    CHECK(gpio_handler_ == &mock_gpio_handler_);
+    return &mock_gpio_handler_;
+  }
+
+  inline testing::NiceMock<UpdateAttempterMock>* mock_update_attempter() {
+    CHECK(update_attempter_ == &mock_update_attempter_);
+    return &mock_update_attempter_;
+  }
+
+  inline OmahaRequestParams* default_request_params() {
+    CHECK(request_params_ == &default_request_params_);
+    return &default_request_params_;
+  }
+
+  inline testing::NiceMock<MockP2PManager>* mock_p2p_manager() {
+    CHECK(p2p_manager_ == &mock_p2p_manager_);
+    return &mock_p2p_manager_;
+  }
+
+  inline chromeos_policy_manager::FakePolicyManager* fake_policy_manager() {
+    CHECK(policy_manager_ == &fake_policy_manager_);
+    return &fake_policy_manager_;
+  }
+
+ private:
+  // Default mock/fake implementations (owned).
+  FakeClock fake_clock_;
+  testing::NiceMock<MockConnectionManager> mock_connection_manager_;
+  FakeHardware fake_hardware_;
+  testing::NiceMock<MetricsLibraryMock> mock_metrics_lib_;
+  testing::NiceMock<PrefsMock> mock_prefs_;
+  testing::NiceMock<PrefsMock> mock_powerwash_safe_prefs_;
+  testing::NiceMock<MockPayloadState> mock_payload_state_;
+  testing::NiceMock<MockGpioHandler> mock_gpio_handler_;
+  testing::NiceMock<UpdateAttempterMock> mock_update_attempter_;
+  OmahaRequestParams default_request_params_;
+  testing::NiceMock<MockP2PManager> mock_p2p_manager_;
+  chromeos_policy_manager::FakePolicyManager fake_policy_manager_;
+
+  // Pointers to objects that client code can override. They are initialized to
+  // the default implementations above.
+  ClockInterface* clock_;
+  ConnectionManager* connection_manager_;
+  HardwareInterface* hardware_;
+  MetricsLibraryInterface* metrics_lib_;
+  PrefsInterface* prefs_;
+  PrefsInterface* powerwash_safe_prefs_;
+  PayloadStateInterface* payload_state_;
+  GpioHandler* gpio_handler_;
+  UpdateAttempter* update_attempter_;
+  OmahaRequestParams* request_params_;
+  P2PManager* p2p_manager_;
+  chromeos_policy_manager::PolicyManager* policy_manager_;
+
+  // Other object pointers (not preinitialized).
+  const policy::DevicePolicy* device_policy_;
+
+  // Other data members.
+  MockDBusWrapper dbus_;
+  bool fake_system_rebooted_;
+};
+
+}  // namespace chromeos_update_engine
+
+#endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_FAKE_SYSTEM_STATE_H_