Pass in the user defined by Context.

The majority of Manager-style classes already use Context.getUserId()
when making calls into the OS, so clean up the remaining callers to
unify behind this strategy.

This gives @SystemApi developers a nice clean interface to interact
across user boundaries, instead of manually adding "AsUser" or
"ForUser" method variants, which would quickly become unsustainable.

Test: builds, boots
Bug: 72863821
Exempt-From-Owner-Approval: trivial changes
Change-Id: Ib772ec4438e57a2ad4950821b9432f9842998451
diff --git a/core/java/android/app/ApplicationPackageManager.java b/core/java/android/app/ApplicationPackageManager.java
index 6b0a2f9..13117bc 100644
--- a/core/java/android/app/ApplicationPackageManager.java
+++ b/core/java/android/app/ApplicationPackageManager.java
@@ -140,6 +140,11 @@
     }
 
     @Override
+    public int getUserId() {
+        return mContext.getUserId();
+    }
+
+    @Override
     public PackageInfo getPackageInfo(String packageName, int flags)
             throws NameNotFoundException {
         return getPackageInfoAsUser(packageName, flags, mContext.getUserId());