From the profile in bug 1196586 comment 2, gaia-header.js takes time doing font fit (~100ms on Flame) when launch Gallery, we can apply gaia-header tweaks [1] to avoid that. [1] https://github.com/gaia-components/gaia-header

With attachment 8652187 [details], on Flame the visullayLoaded gets ~80ms faster (1218ms to 1140ms). The first time removing "no-font-fit" attribute takes ~50ms if there's a reflow, and ~20ms for header has both attributes title-start and title-end.

Comment on attachment 8652187 [details] [gaia] janus926:bug-1198132 > mozilla-b2g:master Ting-Yu, Thank you for working on this. Overall this patch looks fine. I'd slightly prefer to have the removeAttribute() code in startup.js instead of in the setView() function, however, so am giving r- for that reason. If you disagree, let's continue the discussion here with needinfos. Also, I'm a little surprised to learn that gaia-header components slow down startup even though none of them are visible when the app starts. I wonder if there is any way that the component could do the font-fit algorithm when it first becomes visible, rather than when it is created. I can't think of how thaat would work, though, so maybe this is not possible. If I was refactoring the gallery today, I'd probably create each of the views (and headers) on demand, rather than loading the entire html file at startup, and we wouldn't have this problem. See my comments on github.

Comment on attachment 8652187 [details] [gaia] janus926:bug-1198132 > mozilla-b2g:master Addressed, thank you for your detailed comments :)

Comment on attachment 8652187 [details] [gaia] janus926:bug-1198132 > mozilla-b2g:master Please add a comment before the code that removes the attributes to explain what it is doing. And consider using for/of instead of [].forEach.call. It looks good to me. Please land it when you're ready. Note that I have not tested the code myself. I know that you have measured the startup time improvement, so I assume you've tested it and that the headers still work even when switching locales (between English and Runtime Accented, for exmample)

(In reply to David Flanagan [:djf] from comment #5) > Please add a comment before the code that removes the attributes to explain > what it is doing. And consider using for/of instead of [].forEach.call. Comment added; use for(;;) instead. > Note that I have not tested the code myself. I know that you have measured > the startup time improvement, so I assume you've tested it and that the > headers still work even when switching locales (between English and Runtime > Accented, for exmample) Tested with different locales and the headers still work. Thanks for reviewing :)

Master: https://github.com/mozilla-b2g/gaia/commit/d55f3327336b3bf3d7b0a9fe2020e968ac0e7a5b