Replace use of GC::alpha() in SVGImage::draw() with GC::getNormalizedAlpha()

As requested in https://codereview.chromium.org/181633002/

BUG=261177

Review URL: https://codereview.chromium.org/182853002

git-svn-id: svn://svn.chromium.org/blink/trunk@168049 bbb929c8-8fbe-4397-9dbb-9b2b20218538
2 files changed
tree: 97a5b81932cca9b05e93d3918594bcfc66fea9f7
  1. third_party/