This CL improves load times by up to 6x. This is achieved by not setting
event handlers per-line, but setting one event handler on the container.

Unfortunately, load times are dominated by the graph view, which needs
to be addressed in another CL.

Bug: v8:7327
Notry: true
Change-Id: Ie9a999f4150617fd763b770fcacca6096f457880
Reviewed-on: https://chromium-review.googlesource.com/c/1384312Reviewed-by: Georg Neis <neis@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58370}