Improve API signature.

There's nothing actionable for someone calling addToWhitelist() if the
addition fails (since it means the package wasn't found), so there's no
reason to have a return value. Removing the return value and clarifying
that calling the API will add the app to the permanent power save
whitelist.

Bug: 149216029
Test: atest PowerWhitelistTest
Change-Id: I54da34703c9f8862fa641f6b0313e6dfa37948e7
diff --git a/apex/jobscheduler/framework/java/android/os/PowerWhitelistManager.java b/apex/jobscheduler/framework/java/android/os/PowerWhitelistManager.java
index 4ffcf8a..4b4fb96 100644
--- a/apex/jobscheduler/framework/java/android/os/PowerWhitelistManager.java
+++ b/apex/jobscheduler/framework/java/android/os/PowerWhitelistManager.java
@@ -80,27 +80,22 @@
     }
 
     /**
-     * Add the specified package to the power save whitelist.
-     *
-     * @return true if the package was successfully added to the whitelist
+     * Add the specified package to the permanent power save whitelist.
      */
     @RequiresPermission(android.Manifest.permission.DEVICE_POWER)
-    public boolean addToWhitelist(@NonNull String packageName) {
-        return addToWhitelist(Collections.singletonList(packageName)) == 1;
+    public void addToWhitelist(@NonNull String packageName) {
+        addToWhitelist(Collections.singletonList(packageName));
     }
 
     /**
-     * Add the specified packages to the power save whitelist.
-     *
-     * @return the number of packages that were successfully added to the whitelist
+     * Add the specified packages to the permanent power save whitelist.
      */
     @RequiresPermission(android.Manifest.permission.DEVICE_POWER)
-    public int addToWhitelist(@NonNull List<String> packageNames) {
+    public void addToWhitelist(@NonNull List<String> packageNames) {
         try {
-            return mService.addPowerSaveWhitelistApps(packageNames);
+            mService.addPowerSaveWhitelistApps(packageNames);
         } catch (RemoteException e) {
             e.rethrowFromSystemServer();
-            return 0;
         }
     }
 
diff --git a/api/system-current.txt b/api/system-current.txt
index 838d23f..7917c35 100755
--- a/api/system-current.txt
+++ b/api/system-current.txt
@@ -8838,8 +8838,8 @@
   }
 
   public class PowerWhitelistManager {
-    method @RequiresPermission(android.Manifest.permission.DEVICE_POWER) public boolean addToWhitelist(@NonNull String);
-    method @RequiresPermission(android.Manifest.permission.DEVICE_POWER) public int addToWhitelist(@NonNull java.util.List<java.lang.String>);
+    method @RequiresPermission(android.Manifest.permission.DEVICE_POWER) public void addToWhitelist(@NonNull String);
+    method @RequiresPermission(android.Manifest.permission.DEVICE_POWER) public void addToWhitelist(@NonNull java.util.List<java.lang.String>);
     method @RequiresPermission(android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST) public void whitelistAppTemporarily(@NonNull String, long);
     method @RequiresPermission(android.Manifest.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST) public long whitelistAppTemporarilyForEvent(@NonNull String, int, @NonNull String);
     field public static final int EVENT_MMS = 2; // 0x2
diff --git a/api/test-current.txt b/api/test-current.txt
index 7e8eb0c..96302bb4 100644
--- a/api/test-current.txt
+++ b/api/test-current.txt
@@ -2450,8 +2450,8 @@
   }
 
   public class PowerWhitelistManager {
-    method @RequiresPermission("android.permission.DEVICE_POWER") public boolean addToWhitelist(@NonNull String);
-    method @RequiresPermission("android.permission.DEVICE_POWER") public int addToWhitelist(@NonNull java.util.List<java.lang.String>);
+    method @RequiresPermission("android.permission.DEVICE_POWER") public void addToWhitelist(@NonNull String);
+    method @RequiresPermission("android.permission.DEVICE_POWER") public void addToWhitelist(@NonNull java.util.List<java.lang.String>);
     method @RequiresPermission("android.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST") public void whitelistAppTemporarily(@NonNull String, long);
     method @RequiresPermission("android.permission.CHANGE_DEVICE_IDLE_TEMP_WHITELIST") public long whitelistAppTemporarilyForEvent(@NonNull String, int, @NonNull String);
     field public static final int EVENT_MMS = 2; // 0x2