Fix valgrind warnings triggered in vertical mode.

Now that Chrome is rendering subpixel text, I was able to try running
the renderer process under valgrind, which turned up a number of
issues.

First, I was calculating the stride of vertical LCD glyphs wrong
(typo).

Secondly, I was going horribly wrong when a glyph was being blitted at
the edge of a bitmap. I suspected something was wrong with the code,
but I wasn't clear enough with the structure of the code when writing
it to figure out what the correct solution was.

http://codereview.appspot.com/97059


git-svn-id: http://skia.googlecode.com/svn/trunk@284 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed