Fix adb command in sample widget comments.
diff --git a/samples/simplevideowidget/src/main/java/com/google/vr/sdk/samples/simplevideowidget/SimpleVrVideoActivity.java b/samples/simplevideowidget/src/main/java/com/google/vr/sdk/samples/simplevideowidget/SimpleVrVideoActivity.java
index ce37fd7..202d6b0 100644
--- a/samples/simplevideowidget/src/main/java/com/google/vr/sdk/samples/simplevideowidget/SimpleVrVideoActivity.java
+++ b/samples/simplevideowidget/src/main/java/com/google/vr/sdk/samples/simplevideowidget/SimpleVrVideoActivity.java
@@ -23,7 +23,7 @@
  * command:
  *   adb shell am start -a android.intent.action.VIEW \
  *     -n com.google.vr.sdk.samples.simplevideowidget/.SimpleVrVideoActivity
- *     -d /sdcard/FILENAME.MP4
+ *     -d file://sdcard/FILENAME.MP4
  */
 public class SimpleVrVideoActivity extends Activity {
   private static final String TAG = SimpleVrVideoActivity.class.getSimpleName();