git cl upload asks for username+password yet you can't use a username+password for https://chromium.googlesource.com you must set up the cookies as shown in the "Generate Password" on https://chromium.googlesource.com/

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tansell@tansell-z620-l2:~/work/chromium/tools/build$ git cl upload
Using 50% similarity for rename/copy detection. Override with --similarity.
Running presubmit upload checks ...

Presubmit checks passed.
 scripts/slave/recipe_modules/chromium_tests/steps.py | 65 +++++++++++++++++++++++++++++++++++++++++++----------------------
 scripts/slave/recipe_modules/isolate/api.py          | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 22 deletions(-)

Username for 'https://chromium.googlesource.com': tansell@chromium.org
Password for 'https://tansell@chromium.org@chromium.googlesource.com': 
remote: Login Required
fatal: Authentication failed for 'https://chromium.googlesource.com/chromium/tools/build/'
Traceback (most recent call last):
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