Hi Behdad,
While further checking Noto fonts, i found that these fonts are same as already packaged google-droid-sans-fonts. I have tested following script fonts.
1. Devanagari: Outline is same in Noto and Droid
2. Tamil : Outline is same in Noto and Droid
3. Armenian: Outline is same in Noto and Droid
Droid looks bit older version 1.02 and Noto is latest version 1.03. Noto has hinting information while Droid is unhinted.
Considering this, i think we can either keep Droid or Noto in fedora. Noto has more preference since its latest version.
If you know difference please update me with it.