Handle updating depot_tools repos that are git cloned.

Until recently, no proper Git clone of depot_tools existed.
All Git clones were set up locally via git svn clone.  The
way repos of that type are updated is via 'git svn rebase'.

Now, a supported Git clone of depot_tools exists.  The
update process for repos of this type is via 'git fetch'
and 'git rebase'.

Modify the update_depot_tools* scripts so they can update
depot_tools for git cloned or git svn cloned methods.  This
also means that git svn is no longer required, so move that
test after we check for git cloned repos.

R=maruel@chromium.org

TEST=Linux + git clone: on Linux, git clone
https://git.chromium.org/chromium/tools/depot_tools.git.  Apply
and commit this patch locally.  Note commit hash of HEAD.  Run
'git reset --hard "HEAD^^^"'.  Run
'git cherry-pick HASH_OF_UPDATE_CHANGE'.  Run './update_depot_tools'.
Verify depot_tools is updated to latest available revision + this
change.

TEST=Linux + git svn clone: on Linux, git svn clone
svn://svn.chromium.org/chrome/trunk/tools/depot_tools.
Apply and commit this patch locally.  Note commit hash
of HEAD.  Run 'git reset --hard "HEAD^^^"'.  Run 'git cherry-pick
HASH_OF_UPDATE_CHANGE'.  Run './update_depot_tools'.  Verify
depot_tools is updated to latest available revision + this change.

TEST=Windows command prompt + git clone: on Windows command prompt,
run Linux+git clone test, except use update_depot_tools.bat.  Verify
depot_tools is updated to latest available revision + this change.

TEST=Windows command prompt + git svn clone: on Windows command
prompt, run Linux+git svn clone test, except use
update_depot_tools.bat.  Verify depot_tools is updated to latest
available revision + this change.

TEST=Windows cygwin + git clone: on Windows command prompt,
run Linux+git clone test.  Verify depot_tools is updated to latest
available revision + this change.

TEST=Windows cygwin + git svn clone: on Windows command
prompt, run Linux+git svn clone test.  Verify depot_tools is updated
to latest available revision + this change.

Review URL: https://chromiumcodereview.appspot.com/10263004

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@134732 0039d316-1c4b-4281-b951-d872f2087c98

update_depot_tools

@@ -63,6 +63,26 @@ function test_git_svn {
   fi
 }
 
+function is_git_clone_repo {
+  "$GIT" config remote.origin.fetch > /dev/null
+}
+
+function update_git_repo {
+  if is_git_clone_repo; then
+    git fetch -q origin > /dev/null
+    git rebase -q origin > /dev/null
+    return 0
+  fi
+
+  test_git_svn
+  # work around a git-svn --quiet bug
+  OUTPUT=`"$GIT" svn rebase -q -q`
+  if [[ ! "$OUTPUT" == *Current.branch* ]]; then
+    echo $OUTPUT 1>&2
+  fi
+  return 0
+}
+
 # Get the current SVN revision.
 get_svn_revision() {
   LANGUAGE=C "$SVN" info "$base_dir" | \
@@ -73,12 +93,7 @@ get_svn_revision() {
 if [ "X$DEPOT_TOOLS_UPDATE" != "X0" -a -e "$base_dir/.git" ]
 then
   cd $base_dir
-  test_git_svn
-  # work around a git-svn --quiet bug
-  OUTPUT=`"$GIT" svn rebase -q -q`
-  if [[ ! "$OUTPUT" == *Current.branch* ]]; then
-    echo $OUTPUT 1>&2
-  fi
+  update_git_repo
   cd - > /dev/null
 fi
 

update_depot_tools.bat

@@ -13,6 +13,8 @@ setlocal
 :: not already in the PATH environment variable.
 call "%~dp0bootstrap\win\win_tools.bat" force
 if errorlevel 1 goto :EOF
+:: Now clear errorlevel so it can be set by other programs later.
+set errorlevel=
 
 :: Shall skip automatic update?
 IF "%DEPOT_TOOLS_UPDATE%" == "0" GOTO :EOF
@@ -31,5 +33,13 @@ goto :EOF
 
 :GIT_UPDATE
 cd /d "%~dp0."
+call git config remote.origin.fetch > NUL
+if errorlevel 1 goto :GIT_SVN_UPDATE
+call git fetch -q origin > NUL
+call git rebase -q origin > NUL
+goto :EOF
+
+:GIT_SVN_UPDATE
+cd /d "%~dp0."
 call git svn rebase -q -q
 goto :EOF