The fix for Bug 9934 causes an assertion failure in debug builds because an integer value is used instead of a floating point value when creating the Length() object. Patch forthcoming with fix and a layout test (per Bug 9934 Comment #4).
Created attachment 12408 [details] Patch v1 Proposed fix and layout test.
Created attachment 12409 [details] Patch v2 Fixed results (Patch v1 had old results).
Comment on attachment 12409 [details] Patch v2 r=me
Committed revision 18824.