Create APIs to interact with DynamicPowerSaver

This creates the PowerManager APIs that allow apps with the
appropriate permissions to interact with Dynamic Power Saver.

Bug: 111450127
Test: WIP
Change-Id: I5b9483fa0fba81a4ade622b1f3dbaec580b68a67
diff --git a/packages/Shell/AndroidManifest.xml b/packages/Shell/AndroidManifest.xml
index 822c39b..89690fb 100644
--- a/packages/Shell/AndroidManifest.xml
+++ b/packages/Shell/AndroidManifest.xml
@@ -83,6 +83,7 @@
     <uses-permission android:name="android.permission.ACCESS_SURFACE_FLINGER" />
     <uses-permission android:name="android.permission.READ_FRAME_BUFFER" />
     <uses-permission android:name="android.permission.DEVICE_POWER" />
+    <uses-permission android:name="android.permission.POWER_SAVER" />
     <uses-permission android:name="android.permission.INSTALL_LOCATION_PROVIDER" />
     <uses-permission android:name="android.permission.BACKUP" />
     <uses-permission android:name="android.permission.FORCE_STOP_PACKAGES" />