PolicyManager: New System provider.

The system provider exposes information about the device from
crossystem and the kernel boot command line options.

BUG=chromium:338587
TEST=Unit tests.

Change-Id: I2837a97740b63562155717cfe6a12fad69fd8cea
Reviewed-on: https://chromium-review.googlesource.com/191121
Reviewed-by: Alex Deymo <deymo@chromium.org>
Tested-by: Alex Deymo <deymo@chromium.org>
Commit-Queue: Alex Deymo <deymo@chromium.org>
diff --git a/policy_manager/fake_state.cc b/policy_manager/fake_state.cc
index 19df440..3dcec18 100644
--- a/policy_manager/fake_state.cc
+++ b/policy_manager/fake_state.cc
@@ -5,6 +5,7 @@
 #include "update_engine/policy_manager/fake_random_provider.h"
 #include "update_engine/policy_manager/fake_shill_provider.h"
 #include "update_engine/policy_manager/fake_state.h"
+#include "update_engine/policy_manager/fake_system_provider.h"
 #include "update_engine/policy_manager/fake_time_provider.h"
 
 namespace chromeos_policy_manager {
@@ -12,6 +13,7 @@
 FakeState::FakeState() {
   set_random_provider(new FakeRandomProvider());
   set_shill_provider(new FakeShillProvider());
+  set_system_provider(new FakeSystemProvider());
   set_time_provider(new FakeTimeProvider());
 }