[Bug 1234343 - Overly large values reported for gfx/heap-textures](https://bugzilla.mozilla.org/show_bug.cgi?id=1234343) (changes size_t to ptrdiff_t (which "was fixed" from int32_t by previous bug) in FF46 (and Mozilla has closed related ticket with that confirmed bug as WORKSFORME for FF45, ugh [Bug 1262088 - Incorrect about:memory reports (gfx/heap-textures) when playing HTML5 videos](https://bugzilla.mozilla.org/show_bug.cgi?id=1262088)) Without it TBB shows ``` │ ├──3,155.00 MB (93.38%) ── heap-textures ``` (As `heap-textures` causes a half of memory leaks, the helper ticket is worth tracking [Bug 1290100 - Decompose explicit/gfx/heap-textures](https://bugzilla.mozilla.org/show_bug.cgi?id=1290100))