commit 4985b226382a88c62a9d921dacab11e393f91c79
author Fredrik Söderquist <fs@opera.com> Thu Mar 07 13:11:55 2019
committer Commit Bot <commit-bot@chromium.org> Thu Mar 07 13:11:55 2019
tree 2f761e119587f137974728d8f1bf381f230f217f
parent 468b222b5108c5abf64b093676084da7e9356bd3

Improve tainting for filter primitives

This makes tainting for many filter primitives less pessimistic, by
implementing the "Tainted Filter Primitives" section [1] from the
specification.

For feFlood/feDropShadow:

  A value of 'currentcolor' for 'flood-color' taints.

For feSpecularLighting/feDiffuseLighting:

  A value of 'currentcolor' for 'lighting-color' taints.

For the other primitives (which currently lack any specific logic), i.e:

  feBlend, feComponentTransfer, feComposite, feConvolveMatrix,
  feDisplacementMap, feGaussianBlur, feMorphology, feOffset and feTile

no local tainting is performed (the TaintsOrigin() override is returning
false).

The signature/convention of the TaintsOrigin() is changed by removing
the |inputs_taint_origin| argument, and always taint the
primitive if it (the flag returned by FilterEffect::InputsTaintOrigin)
is true. This saves each primitive to have to relate to this flag. (For
primitives that have no inputs this flag would always be false
regardless.) This means that TaintsOrigin() for each primitive is now
essentially computing the "local" tainting state.

[1] https://drafts.fxtf.org/filter-effects/#tainted-filter-primitives

Bug: 792518
Change-Id: Ie2d45eeb1ae8478009b88b8b87b3c4c325ede306
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1503257
Commit-Queue: Fredrik Söderquist <fs@opera.com>
Reviewed-by: Philip Rogers <pdr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638546}