Merge pull request #13653 from huchengtw-moz/gallery/Bug_935072_crop_handle_hard_to_grab

Bug 935072 - [B2G][Gallery] Crop handles are difficult to grab and move, r=djf(cherry picked from commit 8d4f461310c53478a0cdc44ecb8ad10fdb647d66)
Merge pull request #13730 from huchengtw-moz/gallery/Bug_935072-v1.2

Merge pull request #13653 from huchengtw-moz/gallery/Bug_935072_crop_han...