Fix a crash caused by missing download ID from system DownloadManager for OMA downloads

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

Index: chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
diff --git a/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
index d47702ee6c9a696b22dca550994f7d76c69fb468..00c85694bb33f6d553f2f19bd63ea5b9d2bacb22 100644
--- a/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
+++ b/chrome/android/java/src/org/chromium/chrome/browser/download/DownloadManagerService.java
@@ -433,8 +433,10 @@ public class DownloadManagerService extends BroadcastReceiver implements
                 mOMADownloadHandler.onDownloadFailed(
                         mDownloadInfo, downloadId, mFailureReason, mInstallNotifyURI);
                 removeOMADownloadFromSharedPrefs(downloadId);
-                String fileName = mDownloadInfo.getFileName();
-                onDownloadFailed(fileName, mFailureReason);
+                if (mDownloadInfo != null) {
+                    String fileName = mDownloadInfo.getFileName();
+                    onDownloadFailed(fileName, mFailureReason);
+                }
             }
         }
     }