Bug 840902. Part 1: Stop checking the results of various display list methods. r=mattwoodrow

--HG--
extra : rebase_source : f90be285148c68fae306d09714f0fe642b490c45
Bug 840902. Part 2: Remove nsresults from various display list methods. r=mattwoodrow

--HG--
extra : rebase_source : 2236b75807639d54a39950d06cd18cfc952659f3