If a download is initiated by download attribute, don't use stream viewer

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 90efe4e0d8731cf1a17e6451b51fb60e25137c41..932cc6d925ff49fceafb40eb311ea91485262cdc 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
@@ -911,19 +911,7 @@ public class DownloadManagerService extends BroadcastReceiver implements
     @VisibleForTesting
     static boolean shouldOpenAfterDownload(DownloadInfo downloadInfo) {
         String type = downloadInfo.getMimeType();
-        return downloadInfo.hasUserGesture() && !isAttachment(downloadInfo.getContentDisposition())
-                && MIME_TYPES_TO_OPEN.contains(type);
-    }
-
-    /**
-     * Returns true if the download meant to be treated as an attachment.
-     *
-     * @param contentDisposition Content disposition of the download.
-     * @return true if the downloaded is an attachment, or false otherwise.
-     */
-    public static boolean isAttachment(String contentDisposition) {
-        return contentDisposition != null
-                && contentDisposition.regionMatches(true, 0, "attachment", 0, 10);
+        return downloadInfo.hasUserGesture() && MIME_TYPES_TO_OPEN.contains(type);
     }
 
     /**