GitLab

In new-style notification, the resizing behavior of image notification
is different form the non-MD notification.
This CL adds LargeImageView, which implements the specific resizing
behavior.

BUG=737850
TEST=manual

Review-Url: https://codereview.chromium.org/2969603003
Cr-Commit-Position: refs/heads/master@{#491992}