PM: New system provider variable for whether OOBE is complete.

This uses logic found in Hardware::IsOOBEComplete(). It is needed for
deciding whether scattering should be applied.

BUG=chromium:358323
TEST=Unit tests.

Change-Id: I745365e84fc09dd234cd5f65ec0a2012a9024cdd
Reviewed-on: https://chromium-review.googlesource.com/200571
Reviewed-by: Alex Deymo <deymo@chromium.org>
Tested-by: Gilad Arnold <garnold@chromium.org>
Commit-Queue: Gilad Arnold <garnold@chromium.org>
diff --git a/policy_manager/fake_system_provider.h b/policy_manager/fake_system_provider.h
index 5886828..d86e015 100644
--- a/policy_manager/fake_system_provider.h
+++ b/policy_manager/fake_system_provider.h
@@ -23,11 +23,17 @@
     return &var_is_official_build_;
   }
 
+  virtual FakeVariable<bool>* var_is_oobe_complete() override {
+    return &var_is_oobe_complete_;
+  }
+
  private:
   FakeVariable<bool> var_is_normal_boot_mode_{
       "is_normal_boot_mode", kVariableModeConst};
   FakeVariable<bool> var_is_official_build_{
       "is_official_build", kVariableModeConst};
+  FakeVariable<bool> var_is_oobe_complete_{
+      "is_oobe_complete", kVariableModePoll};
 
   DISALLOW_COPY_AND_ASSIGN(FakeSystemProvider);
 };