Change code review host to Chromium's Rietveld.

Change code review host to Chromium's Rietveld.

Since WebRTC's codereview instance at webrtc-codereview.appspot.com
is going to be read-only, libyuv needs to switch to Chromium's instance.

Also update the ViewVC URL to match the Git repo that is now the
master repo.

After this CL has landed, existing Git branches will continue to remember which Rietveld URL they uploaded to.
To reset a branch and re-upload a new CL to the new instance, do like this:
git cl issue 0
git pull --rebase origin master
git cl upload

BUG=libyuv:450
R=fbarchard@chromium.org

Committed: https://chromium.googlesource.com/libyuv/libyuv/+/3f893126a56e1e922090b7fb20f8f65a340433d0

[kjellander_chromium, 2015-06-05 08:35:02]

kjellander@chromium.org changed reviewers:
+ fbarchard@chromium.org

[fbarchard, 2015-06-05 17:22:42]

Any implications?

[kjellander_chromium, 2015-06-06 15:58:19]

On 2015/06/05 17:22:42, fbarchard wrote:
> Any implications?

Absolutely. See my e-mail for all details.

[fbarchard, 2015-09-05 01:48:54]

lgtm

[kjellander_chromium, 2015-09-06 04:37:14]

Updated the CL description with more details. Will commit this now and send a
PSA to the committers.

[kjellander_chromium, 2015-09-06 04:49:07]

Committed patchset #2 (id:20001) manually as
3f893126a56e1e922090b7fb20f8f65a340433d0 (presubmit successful).