build: validate Chromium cookie authentication (#46326)

Co-authored-by: trop[bot] <37223003+trop[bot]@users.noreply.github.com>
Co-authored-by: Shelley Vohr <shelley.vohr@gmail.com>

.github/actions/set-chromium-cookie/action.yml

@@ -17,6 +17,16 @@ runs:
       ${{ env.CHROMIUM_GIT_COOKIE }}
       __END__
       eval 'set -o history' 2>/dev/null || unsetopt HIST_IGNORE_SPACE 2>/dev/null
+
+      RESPONSE=$(curl -s -b ~/.gitcookies https://chromium-review.googlesource.com/a/accounts/self)
+      if [[ $RESPONSE == ")]}'"* ]]; then
+        # Extract account email for verification
+        EMAIL=$(echo "$RESPONSE" | tail -c +5 | jq -r '.email // "No email found"')
+        echo "Cookie authentication successful - authenticated as: $EMAIL"
+      else
+        echo "Cookie authentication failed - ensure CHROMIUM_GIT_COOKIE is set correctly"
+        echo $RESPONSE
+      fi
   - name: Set the git cookie from chromium.googlesource.com (Windows)
     if: ${{ runner.os == 'Windows' && env.CHROMIUM_GIT_COOKIE_WINDOWS_STRING }}
     shell: cmd
@@ -24,3 +34,15 @@ runs:
       git config --global http.cookiefile "%USERPROFILE%\.gitcookies"
       powershell -noprofile -nologo -command Write-Output "${{ env.CHROMIUM_GIT_COOKIE_WINDOWS_STRING }}" >>"%USERPROFILE%\.gitcookies"
 
+      curl -s -b "%USERPROFILE%\.gitcookies" https://chromium-review.googlesource.com/a/accounts/self > response.txt
+
+      findstr /B /C:")]}'" response.txt > nul
+      if %ERRORLEVEL% EQU 0 (
+        echo Cookie authentication successful
+        powershell -NoProfile -Command "& {$content = Get-Content -Raw response.txt; $content = $content.Substring(4); try { $json = ConvertFrom-Json $content; if($json.email) { Write-Host 'Authenticated as:' $json.email } else { Write-Host 'No email found in response' } } catch { Write-Host 'Error parsing JSON:' $_ }}"
+      ) else (
+        echo Cookie authentication failed - ensure CHROMIUM_GIT_COOKIE_WINDOWS_STRING is set correctly
+        type response.txt
+      )
+
+      del response.txt