GitLab

SetSubText() in HoverHighlight view should not be called
if the parameter string is empty, otherwise multi-line
rows in the system menu will have the incorrect layout
of their primary text.

BUG=715615
TEST=manual

Review-Url: https://codereview.chromium.org/2844933003
Cr-Commit-Position: refs/heads/master@{#467813}