The amazing new delayed snippet/body fetching is causing some bad scrolling problems for me on messages where generateSnippet is returning ''. The 2 key things: 1) maybeRequestSnippets uses !snippet to detect there not being a snippet, which does not distinguish between null (no snippet) and '' (empty snippet). We should explicitly null-check rather than falsey-check. This covers text/plain and text/html. 2) generateSnippet currently only likes to return CT_AUTHORED_CONTENT. We want a fallback mode for generateSnippet where it makes a second pass and is willing to use the CT_QUOTED_TYPE, although we should re-prefix '>' characters so it's clear we've fallen back to quoted text. Note that we keep the 'Bob wrote:' stuff as CT_LEADIN_TO_QUOTE, so there are no worries about having that useful bit of text in there.

Bug 814257 has addressed point 1, so this bug should now only be about point 2.

Firefox OS is not being worked on