tree 1baee6ae466153c703cf7ebd82b089e688d22935
parent 5bca5ca83624d2ba8df064cb888c2f27ab248097
author npm <npm@chromium.org> 1477684068 -0700
committer Commit bot <commit-bot@chromium.org> 1477684068 -0700

Use CompositeMask instead of TransferBitmap when drawing type 3 text

TransferBitmap seems to work improperly when the glyph boxes overlap.
In particular, after drawing a glyph, the next glyph's blanks will
override what the previous glyph drew, and this is not the correct
behavior. While on it, use CheckedNumeric to do operations safely.
For reference of somewhere where something similar is done, see:
https://cs.chromium.org/chromium/src/third_party/pdfium/core/fxge/ge/cfx_renderdevice.cpp?sq=package:chromium&rcl=1477581616&l=988

BUG=513954

Review-Url: https://codereview.chromium.org/2461743002