Revert of git cl: Rework Changelist class for Rietveld/Gerrit use. (patchset #1 id:1 of https://codereview.chromium.org/1844523002/ )

Reason for revert:
argh, CQ is way too quick.

Original issue's description:
> Reland of git cl: Rework Changelist class for Rietveld/Gerrit use. (patchset #1 id:1 of https://codereview.chromium.org/1840833002/ )
> 
> Reason for revert:
> with a fix.
> 
> Original issue's description:
> > Revert of git cl: Rework Changelist class for Rietveld/Gerrit use. (patchset #3 id:40001 of https://codereview.chromium.org/1830973003/ )
> > 
> > Reason for revert:
> > Speculative revert, see crbug.com/598428.
> > 
> > Original issue's description:
> > > git cl: Rework Changelist class for Rietveld/Gerrit use.
> > > 
> > > This adds pluggable codereview-specific implementations into
> > > Changelist class. The specific implementation is chosen at
> > > Changelist automatically, with Rietveld being default for
> > > backwards compatibility.
> > > 
> > > Gerrit implementation for Gerrit is incomplete, and will be
> > > added in later CLs. However, it is sufficient to ensure
> > > current functionality of this tool is not diminished.
> > > 
> > > Sadly, the base class isn't completely free from Rietveld
> > > assumptions because of presubmit_support. Apparently, PRESUBMIT
> > > scripts can make use of Rietveld instance for RPCs directly.
> > > This use doesn't make sense for Gerrit, which substitutes
> > > rietveld instance with a dummy object, which raises exception
> > > on any attribute access with a diagnostic message.
> > > 
> > > This also includes refactoring of some related code which
> > > (ab)used ChangeList. Overall, this CL adds a few extra call to
> > > git config in order to determine which codereview to use, but
> > > but it shouldn't have any performance impact.
> > > 
> > > 
> > > 
> > > These is a reland of these 4 CLs + a fix.
> > > patch from issue 1827523003 at patchset 20001 (http://crrev.com/1827523003#ps20001)
> > > patch from issue 1830703004 at patchset 1 (http://crrev.com/1830703004#ps1)
> > > patch from issue 1830923002 at patchset 60001 (http://crrev.com/1830923002#ps60001)
> > > patch from issue 1805193002 at patchset 380001 (http://crrev.com/1805193002#ps380001)
> > > 
> > > 
> > > 
> > > R=machenbach@chromium.org,sergiyb@chromium.org,andybons@chromium.org
> > > BUG=579160,597638
> > > 
> > > Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=299506
> > 
> > TBR=andybons@chromium.org,machenbach@chromium.org,sergiyb@chromium.org,tandrii@chromium.org
> > # Skipping CQ checks because original CL landed less than 1 days ago.
> > NOPRESUBMIT=true
> > NOTREECHECKS=true
> > NOTRY=true
> > BUG=579160,597638
> > 
> > Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=299515
> 
> TBR=andybons@chromium.org,machenbach@chromium.org,sergiyb@chromium.org,dnj@chromium.org
> # Skipping CQ checks because original CL landed less than 1 days ago.
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=579160,597638
> 
> Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=299528

TBR=andybons@chromium.org,machenbach@chromium.org,sergiyb@chromium.org,dnj@chromium.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=579160,597638

Review URL: https://codereview.chromium.org/1839973002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@299529 0039d316-1c4b-4281-b951-d872f2087c98