[PDF Ink Signatures] Handle rotation in GetCanonicalToPdfTransform()

PDF pages can have `/Rotate N` values to rotate the page by 90 degree
increments. This is not being accounted for, similar to how the crop box
was not accounted for in https://crbug.com/402043701.

Fix this issue by rewriting GetCanonicalToPdfTransform() to take the
rotation into account. As a result of this extra transformation,
GetCanonicalToPdfTransform() now has to know the page size, and return
gfx::Transform instead of gfx::AxisTransform2d.

To support this CL:

- Move enum class Rotation into its own file and rename it to
  PageRotation.
- Add GetPageRotation() to consolidate PDFium code that get page
  rotation.

To test this CL:

- Rewrite PdfInkTransformTest.GetCanonicalToPdfTransform to handle all
  rotations. Instead of testing the properties of the resulting
  gfx::AxisTransform2d, call gfx::Transform::MapPoint() to make sure it
  can do the mapping properly.
- Add PDFiumEngineInkDrawTest.RotatedPdf to render strokes on one of the
  rotated pages in rotated_multi_page_cropped.pdf.

Bug: 410442721
Change-Id: I8554b9edabc89d5b8e23ef62d8d5ddb0ad538c14
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6460776
Reviewed-by: Andy Phan <andyphan@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1447818}