Implement staged directory clean up for staged install

Staged files should be deleted from /data/staging once installation
is complete, regardless of failure or success. If a session fails
pre-reboot verification, then it can be deleted before reboot.

Bug: 123624108
Test: manual testing
      - create two apex files; aosp signed and dev signed
      - flash device with internal master
      - aosp signed apex file will fail pre-reboot verification
      - check that files are deleted in /data/staging
      - repeat with multiple package
      - dev signed package passes pre-reboot verification
      - on reboot, files should be deleted from /data/staging

Change-Id: I44a6cc72de26ad0216942623edb6e279c628d58d

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

@@ -1998,6 +1998,7 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
             mStagedSessionErrorMessage = errorMessage;
             Slog.d(TAG, "Marking session " + sessionId + " as failed: " + errorMessage);
         }
+        cleanStageDir();
         mCallback.onStagedSessionChanged(this);
     }
 
@@ -2009,7 +2010,9 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
             mStagedSessionFailed = false;
             mStagedSessionErrorCode = SessionInfo.STAGED_SESSION_NO_ERROR;
             mStagedSessionErrorMessage = "";
+            Slog.d(TAG, "Marking session " + sessionId + " as applied");
         }
+        cleanStageDir();
         mCallback.onStagedSessionChanged(this);
     }
 
@@ -2064,6 +2067,19 @@ public class PackageInstallerSession extends IPackageInstallerSession.Stub {
         }
     }
 
+    private void cleanStageDir() {
+        if (isMultiPackage()) {
+            for (int childSessionId : getChildSessionIds()) {
+                mSessionProvider.getSession(childSessionId).cleanStageDir();
+            }
+        } else {
+            try {
+                mPm.mInstaller.rmPackageDir(stageDir.getAbsolutePath());
+            } catch (InstallerException ignored) {
+            }
+        }
+    }
+
     void dump(IndentingPrintWriter pw) {
         synchronized (mLock) {
             dumpLocked(pw);