Comment 1 for bug 677551

Profile (on Mac) says 95% of the time is spent in the reflow that we trigger from EndUpdateViewBatch. Even more interestingly, 93% is under nsLineLayout::TrimTrailingWhiteSpace and almost all of this is under EnsureTextRun. Sounds like we're recreating textruns for the whole thing, presumably because inserting some text marked them all dirty?

Oh, and we're spending most of our time here on line-breaking in the textrun code.

Are we trying to trim trailing whitespace all down the line, or are we just creating huge textrun? I thought we limited textrun length or something... and we shouldn't have to trim trailing whitespace all down the line (and in fact, should be able to stop the reflow at the next line that ends in a newline char, yes?)