Add Context.getNoBackupFilesDir()

This is an app-private filesystem space exactly like the one
reported by Context.getFilesDir(), with one exception:  files
placed here are never backed up by the full-backup infrastructure.
If an app attempts to back up any of its contents via the normal
API it's immediately ignored with a logged warning.

The restriction is also enforced on the restore side, because
apps using support libraries might wind up creating full backup
archives containing no_backup subdirs on pre-L devices (via
adb backup, Helium, &c.).  We check for this before passing the
restore data to the app, and drop it if we detect the situation
so that the app never sees the bits.

Bug 16240573

Change-Id: I11216a391f1d32117ec7ce15aafc9cd93d0337de

1 files changed, 5 insertions, 0 deletions

diff --git a/test-runner/src/android/test/mock/MockContext.java b/test-runner/src/android/test/mock/MockContext.java
index a54936b..2ebce9b 100644
--- a/test-runner/src/android/test/mock/MockContext.java
+++ b/test-runner/src/android/test/mock/MockContext.java
@@ -175,6 +175,11 @@ public class MockContext extends Context {
     }
 
     @Override
+    public File getNoBackupFilesDir() {
+        throw new UnsupportedOperationException();
+    }
+
+    @Override
     public File getExternalFilesDir(String type) {
         throw new UnsupportedOperationException();
     }