Make package handling in openContentUri more robust

                // signature we just use the first package in the UID. For shared

                // UIDs we may blame the wrong app but that is Okay as they are

                // in the same security/privacy sandbox.

                final AndroidPackage androidPackage = mPackageManagerInt

                        .getPackage(Binder.getCallingUid());

                final int uid = Binder.getCallingUid();

                // Here we handle some of the special UIDs (mediaserver, systemserver, etc)

                final String packageName = AppOpsManager.resolvePackageName(uid,

                        /*packageName*/ null);

                final AndroidPackage androidPackage;

                if (packageName != null) {

                    androidPackage = mPackageManagerInt.getPackage(packageName);

                } else {

                    androidPackage = mPackageManagerInt.getPackage(uid);

                }

                if (androidPackage == null) {

                    Log.e(TAG, "Cannot find package for uid: " + uid);

                    return null;

                }

                final AttributionSource attributionSource = new AttributionSource(

                        Binder.getCallingUid(), androidPackage.getPackageName(), null);

                pfd = cph.provider.openFile(attributionSource, uri, "r", null);