GitLab

-Adds logic to correctly resize on orientation changes.
-Adds logic to set clip bounds on resize
  (i.e. image loads or context menu shows/hides all of the link text).
-Sets rounded corners programmatically instead of in the context menu's xml file.

Note: this does not handle the image loading or link text view enlargement animations.

BUG=730329

Review-Url: https://codereview.chromium.org/2960743002
Cr-Commit-Position: refs/heads/master@{#488506}