GitLab

Move tough_image_decode_cases into the rendering folder and refactor
classes to inherit from RenderingStory

Bug: 849392
Change-Id: I888b1226bc8663c28d79e5871215547af1052b4a
Reviewed-on: https://chromium-review.googlesource.com/1089203
Commit-Queue: Amy Qiu <amyqiu@google.com>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Cr-Commit-Position: refs/heads/master@{#565049}