Set multipart/related mime type again for download pages on Android 10

Android Q's MediaStore.Downloads has an issue that the custom mime type which is not
supported by MimeTypeMap is overridden to "application/octet-stream" when publishing.
To deal with this issue we set the mime type again after publishing.

Bug: 1010829
Change-Id: Ia33cafa25f87095d1f21553c3dcd23bcee96d0ff
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1839151Reviewed-by: Peter Williamson <petewil@chromium.org>
Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#703141}

chrome/android/java/src/org/chromium/chrome/browser/offlinepages/OfflinePageArchivePublisherBridge.java

@@ -203,6 +203,15 @@ public class OfflinePageArchivePublisherBridge {
             Log.d(TAG, "Failed to finish publishing archive.");
         }
 
+        // Android Q's MediaStore.Downloads has an issue that the custom mime type which is not
+        // supported by MimeTypeMap is overridden to "application/octet-stream" when publishing.
+        // To deal with this issue we set the mime type again after publishing.
+        // See crbug.com/1010829 for more details.
+        final ContentValues mimeTypeValues = new ContentValues();
+        mimeTypeValues.put(MediaColumns.MIME_TYPE, "multipart/related");
+        if (contentResolver.update(intermediateUri, mimeTypeValues, null, null) != 1) {
+            Log.d(TAG, "Failed to update mime type.");
+        }
         return intermediateUri.toString();
     }
 }