GitLab

Move image_decoding_cases into rendering folder and modify to inherit
from RenderingStory class

Bug: 849392
Change-Id: I56b02c60c1f674f7c48b8bf378b8bc92f68f4205
Reviewed-on: https://chromium-review.googlesource.com/1089290
Commit-Queue: Amy Qiu <amyqiu@google.com>
Reviewed-by: Ned Nguyen <nednguyen@google.com>
Cr-Commit-Position: refs/heads/master@{#565377}