On Thu, Sep 13, 2012 at 9:05 PM, Maciej Stachowiak <m...@apple.com> wrote: > On Sep 13, 2012, at 11:15 PM, Darin Fisher <da...@google.com> wrote: > On Thu, Sep 13, 2012 at 6:16 PM, Adam Barth <aba...@webkit.org> wrote: >> On Thu, Sep 13, 2012 at 5:13 PM, Adam Barth <aba...@webkit.org> wrote: >> > Another metric we have is for Blob.webkitSlice: >> > >> > Ratio of Blob.webkitSlice calls to Blob.slice: 14.87% >> > Ratio of Blob.webkitSlice calls to Document creation: 0.0053% >> > >> > It's difficult to know how to interpret this data because we don't >> > actually correlate calls to webkitSlice with Documents or Pages. >> > Instead, we just count the total number of calls across all Documents. >> > This gives us an upper bound on how many Documents (or Pages) would >> > be affected by deleting Blob.webkitSlice, but doesn't measure that >> > information as accurately as the data we have for mutation events. >> >> Based on this data, I've posted a patch for removing Blob.webkitSlice >> in favor of Blob.slice: >> >> https://bugs.webkit.org/show_bug.cgi?id=96715 >> >> Adam > > > So, worst case 53 out of a million pages calls webkitSlice. But, it is easy > to imagine that that upper bound is crazy high, and more likely a couple > pages simply call webkitSlice a lot. Also, given that there are so many > more calls to Blob.slice() one could imagine that sites that call > webkitSlice probably have fallback to Blob.slice(). Is this the hypothesis? > > > Adam's data measures webkitSlice() *calls*, not just appearances of the > symbol, so these are either sites that have fallback in the wrong direction > (trying the prefixed version before the vanilla version), or would break > after the removal. I've seen both problems with about similar frequency in > the past, so a decent hypothesis is that half those webkitSlice calls will > break. > > Safari hasn't had Blob for very long at all, so Chrome is probably more > impacted. From my own perspective, I think the usage is low enough that it's > worth making the change to see the fallout. > > I wonder also how likely it is that some of the webkitSlice uses are on > Google-controlled Web properties and therefore could be fixed ahead of time.
By the way, in preparing the patch, I noticed that webkitSlice was used by the web inspector. Note that the data above includes the use by the web inspector. Adam _______________________________________________ webkit-dev mailing list webkit-dev@lists.webkit.org http://lists.webkit.org/mailman/listinfo/webkit-dev
