As discussed in https://bit.ly/3qtrn9s we want to use gfx::PointF for
scroll offset (out of blink renderer) and gfx::Vector2dF for scroll
delta, instead of gfx::Vector2dF for both, for the following purposes:
1. To make it easier to do the correct thing: passing blink scroll
position (currently using FloatPoint, will be changed to gfx::PointF)
to out-of-blink scroll offset (and vice versa); and to make it
difficult to do the incorrect thing: passing blink scroll offset [1]
to out-of-blink scroll offset. Without this CL, the incorrect thing
would be easier to do than the correct thing because of the data
type mismatches.
2. We can better distinguish scroll offset and scroll delta with
different data types.
3. Make it consistent to use gfx::Point[F] for absolute scroll offsets
throughout Chromium.
[1] See third_party/blink/core/layout/README.md for detailed explanation
for of scroll position and scroll offset in blink renderer.
Bug: 738465
Change-Id: Ic9ac9658b8f3154514608ef4039780d0f20883bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3267944
Reviewed-by: Bo <boliu@chromium.org>
Reviewed-by: Steve Kobes <skobes@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Kentaro Hara <haraken@chromium.org>
Owners-Override: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/main@{#941498}
b1973a98d6