One thing to note here is that the Scale function on gfxRect has a
different implementation than that in gfx::Rect which is replacing it.
The former just scales the width/height directly whereas the latter
scales the XMost/YMost and recomputes the width/height.
MozReview-Commit-ID: 5FImdIaNfC3
The bulk of this commit was generated by running:
run-clang-tidy.py \
-checks='-*,llvm-namespace-comment' \
-header-filter=^/.../mozilla-central/.* \
-fix