Android: Allow opening/getting files relative to downloads directory

src/common/file_system.h

@@ -145,11 +145,15 @@ void SanitizeFileName(std::string& Destination, bool StripSlashes = true);
 bool IsAbsolutePath(const std::string_view& path);
 
 /// Removes the extension of a filename.
-std::string StripExtension(const std::string_view& path);
+std::string_view StripExtension(const std::string_view& path);
 
 /// Replaces the extension of a filename with another.
 std::string ReplaceExtension(const std::string_view& path, const std::string_view& new_extension);
 
+/// Returns the display name of a filename. Usually this is the same as the path, except on Android
+/// where it resolves a content URI to its name.
+std::string GetDisplayNameFromPath(const std::string_view& path);
+
 /// Returns the directory component of a filename.
 std::string_view GetPathDirectory(const std::string_view& path);