Adding additional check for zero-sized snapshot.

Bug: 62727429
Test: Not reproducible, just adding check
Change-Id: I1fd5aa43ffb6f211881d5c198c10ee1451666970
diff --git a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
index 297e288..b628869 100644
--- a/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
+++ b/services/core/java/com/android/server/wm/TaskSnapshotPersister.java
@@ -25,6 +25,7 @@
 import android.graphics.Bitmap;
 import android.graphics.Bitmap.CompressFormat;
 import android.graphics.Bitmap.Config;
+import android.graphics.GraphicBuffer;
 import android.os.Process;
 import android.os.SystemClock;
 import android.util.ArraySet;
@@ -325,6 +326,15 @@
             final File file = getBitmapFile(mTaskId, mUserId);
             final File reducedFile = getReducedResolutionBitmapFile(mTaskId, mUserId);
             final Bitmap bitmap = Bitmap.createHardwareBitmap(mSnapshot.getSnapshot());
+            if (bitmap == null) {
+                Slog.e(TAG, "Invalid task snapshot");
+                return false;
+            } else if (bitmap.getWidth() == 0 || bitmap.getHeight() == 0) {
+                Slog.e(TAG, "Invalid task snapshot dimensions " + bitmap.getWidth() + "x"
+                        + bitmap.getHeight());
+                return false;
+            }
+
             final Bitmap swBitmap = bitmap.copy(Config.ARGB_8888, false /* isMutable */);
             final Bitmap reduced = Bitmap.createScaledBitmap(swBitmap,
                     (int) (bitmap.getWidth() * REDUCED_SCALE),