Perf: reflect the state of the plot into the URL when hiding traces.
Perf: reflect the state of the plot into the URL when hiding traces.

BUG=skia:

Change-Id: I342bde816dc5ff954335fe2dcde148c3562ed1ea
Reviewed-on: https://skia-review.googlesource.com/8236
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot