Bug 931843 - Part 0: Tidy up constants in TopSitesGridItemView. r=kats, a=bajaj
Bug 931843 - Part 1: Generate smaller thumbnails. r=kats, a=bajaj
Bug 931843 - Part 2: Rewrite OnFaviconLoadedListeners to hold fewer references. r=bnicholson, a=bajaj
Bug 931843 - Part 3: Don't retain thumbnails. r=bnicholson, a=bajaj
Bug 935157 - Correctly cache favicons by favicon URL, not page URL, and don't log page URLs on failure. r=margaret, a=bajaj