Introduce ImageResourceContent::IntrinsicSize

Most non-layout/paint users that query the size of an image are
interested in the intrinsic size of the image (usually the physical
pixel dimensions.) This is currently achieved by calling the ImageSize()
method with a multiplier of 1.
Split the ImageSize() method into a part that extracts the size of the
image (if any) and one that applies the multiplier (and follow-on
adjustments.) This should allow a future cleanup where the scaling is
moved closer to the layer that uses it - i.e layout and paint.

This also reduces the type-impedance a bit since IntrinsicSize can just
return an IntSize (like Image::Size()) rather than passing through a
LayoutSize.

Bug: 773272
Change-Id: I18a1c11e9fc891dc6f19c4b2c5bd5dc23c1a5da7
Reviewed-on: https://chromium-review.googlesource.com/718747
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Cr-Commit-Position: refs/heads/master@{#509770}
9 files changed