Add PrepareUpdateService.

It's moved from PrepareStreamingService intent service.
Now PrepareUpdateService takes an UpdateConfig and
builds PayloadSpec for UpdateEngine for both streaming
and non-streaming update.

It allows us to do all preparations in intent service's
thread, without blocking UI.

We will also add checksum verification to
PrepareUpdateService.

Test: device, junit
Bug: 77150191
Change-Id: Iea69acd9aa41e17538c26aff60f7598093ca7744
diff --git a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
index fc9fddd..6d1e4c3 100644
--- a/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
+++ b/updater_sample/src/com/example/android/systemupdatersample/ui/MainActivity.java
@@ -21,6 +21,7 @@
 import android.graphics.Color;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Handler;
 import android.os.UpdateEngine;
 import android.util.Log;
 import android.view.View;
@@ -34,7 +35,6 @@
 import com.example.android.systemupdatersample.UpdateConfig;
 import com.example.android.systemupdatersample.UpdateManager;
 import com.example.android.systemupdatersample.UpdaterState;
-import com.example.android.systemupdatersample.util.PayloadSpecs;
 import com.example.android.systemupdatersample.util.UpdateConfigs;
 import com.example.android.systemupdatersample.util.UpdateEngineErrorCodes;
 import com.example.android.systemupdatersample.util.UpdateEngineStatuses;
@@ -67,7 +67,7 @@
     private List<UpdateConfig> mConfigs;
 
     private final UpdateManager mUpdateManager =
-            new UpdateManager(new UpdateEngine(), new PayloadSpecs());
+            new UpdateManager(new UpdateEngine(), new Handler());
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {