Android: Most browsers will allow you to download a million copies of the same file, simply appending a "(1)" or "(2)" to the file name to distinguish between them. If you're running Chrome Beta on Android, the newest version will offer to replace the existing file or create a new one before downloading.
The feature is a small change, but a welcome one on a platform where storage space comes at a premium. For reasons unknown, most browsers don't perform a check on the Downloads folder to see if a particular file already exists before acquiring a second (or tenth) copy. No word yet on whether this functionality will come to other versions of Chrome, but it's most needed where it is.