We were using the c++11 iterator return value from std::map::erase. Instead use the post-increment operator to keep a valid iterator after the call to erase, even on older stl. BUG=angle:773 Change-Id: Ieaa21a2b5a3fcd5ca229a31d40bdf9b8f3283a3c Reviewed-on: https://chromium-review.googlesource.com/238440Tested-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Geoff Lang <geofflang@chromium.org>
