update_engine: Make policy UpdateCheckParams processing easier

Currently there are a ton of arguments from UpdateCheckParams that is
passed around in the udpate_attampter.cc. With this CL UpdateCheckParams
is directy passed and this simplies the logic.

BUG=b:171829801
TEST=cros_workon_make --board reef --test update_enigne

Change-Id: If454f6393fc6e28d41fa5d14d184f0db32e8bd19
Reviewed-on: https://chromium-review.googlesource.com/c/aosp/platform/system/update_engine/+/2504453
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Tested-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Jae Hoon Kim <kimjae@chromium.org>
diff --git a/real_system_state.cc b/real_system_state.cc
index 74a37f3..924271e 100644
--- a/real_system_state.cc
+++ b/real_system_state.cc
@@ -138,7 +138,7 @@
   // will be re-initialized before every request using the actual request
   // options. This initialization here pre-loads current channel and version, so
   // the DBus service can access it.
-  if (!request_params_.Init("", "", false)) {
+  if (!request_params_.Init("", "", {})) {
     LOG(WARNING) << "Ignoring OmahaRequestParams initialization error. Some "
                     "features might not work properly.";
   }