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The non-full reports capture about the same info and load much faster.
We can always switch them back, but thought it's worth trying them for a
while to see if there are any drawbacks.

Also adds a note about opening the viewer directly for uploading files.

Results of this commit are already pushed to
https://storage.googleapis.com/chrome-supersize/index.html

Bug: 880671
Change-Id: I79f1b2298658cde0564c5976f47382e930f7196a
Reviewed-on: https://chromium-review.googlesource.com/c/1281174
Commit-Queue: agrieve <agrieve@chromium.org>
Reviewed-by: Eric Stevenson <estevenson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#599821}