Fixed a crash

Bug: 1006817
Change-Id: I122fc9c2db8ef6fc0c62a4c31722538860fc1286
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1819885Reviewed-by: Min Qin <qinmin@chromium.org>
Commit-Queue: Shakti Sahu <shaktisahu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#699096}

chrome/android/java/src/org/chromium/chrome/browser/download/DownloadSnackbarController.java

@@ -129,8 +129,9 @@ public class DownloadSnackbarController implements SnackbarManager.SnackbarContr
     }
 
     private boolean isShowingDownloadInfoBar() {
-        return DownloadManagerService.getDownloadManagerService()
-                .getInfoBarController(Profile.getLastUsedProfile().isOffTheRecord())
-                .isShowing();
+        DownloadInfoBarController infoBarController =
+                DownloadManagerService.getDownloadManagerService().getInfoBarController(
+                        Profile.getLastUsedProfile().isOffTheRecord());
+        return infoBarController == null ? false : infoBarController.isShowing();
     }
 }