Always restart apps if base.apk gets updated.

Bug: 219044664
Fixes: 219044664
Test: atest PackageManagerShellCommandTest
Change-Id: I27a0c5009b2d5f1ea51618b9acfa1e6ccee71296

core/java/android/content/pm/IPackageInstallerSession.aidl

@@ -57,4 +57,5 @@ interface IPackageInstallerSession {
     int getParentSessionId();
 
     boolean isStaged();
+    int getInstallFlags();
 }

core/java/android/content/pm/PackageInstaller.java

@@ -1585,6 +1585,18 @@ public class PackageInstaller {
             }
         }
 
+        /**
+         * @return Session's {@link SessionParams#installFlags}.
+         * @hide
+         */
+        public int getInstallFlags() {
+            try {
+                return mSession.getInstallFlags();
+            } catch (RemoteException e) {
+                throw e.rethrowFromSystemServer();
+            }
+        }
+
         /**
          * @return the session ID of the multi-package session that this belongs to or
          * {@link SessionInfo#INVALID_ID} if it does not belong to a multi-package session.

services/core/java/com/android/server/pm/PackageInstallerSession.java

@@ -2860,6 +2860,9 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
                 inheritFileLocked(mResolvedBaseFile);
                 // Collect the requiredSplitTypes from base
                 CollectionUtils.addAll(requiredSplitTypes, existing.getBaseRequiredSplitTypes());
+            } else {
+                // Installing base.apk. Make sure the app is restarted.
+                params.setDontKillApp(false);
             }
 
             // Inherit splits if not overridden.
@@ -3555,6 +3558,11 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
         return params.isStaged;
     }
 
+    @Override
+    public int getInstallFlags() {
+        return params.installFlags;
+    }
+
     @Override
     public DataLoaderParamsParcel getDataLoaderParams() {
         mContext.enforceCallingOrSelfPermission(Manifest.permission.USE_INSTALLER_V2, null);