Prompt for cipd authentication if 'cipd ensure' fails.

That should be the only reason that 'cipd ensure' ever fails when downloading
the macOS toolchain. Currenlty this is unnecessary because the check already
exists when installing the old toolchain. But this will become necessary after
removing the old toolchain.

Bug: 984746
Change-Id: Icfd51072207e0e140c6059892d665d306b32e32a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1711149
Commit-Queue: Erik Chen <erikchen@chromium.org>
Auto-Submit: Erik Chen <erikchen@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#679740}

build/mac_toolchain.py

@@ -152,8 +152,16 @@ def InstallXcodeBinaries():
   args = [
       'cipd', 'ensure', '-root', binaries_root, '-ensure-file', '-'
   ]
-  p = subprocess.Popen(args, stdin=subprocess.PIPE)
-  p.communicate(input=MAC_BINARIES_LABEL + ' ' + MAC_BINARIES_TAG)
+  p = subprocess.Popen(
+      args, stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+      stderr=subprocess.PIPE)
+  stdout, stderr = p.communicate(
+      input=MAC_BINARIES_LABEL + ' ' + MAC_BINARIES_TAG)
+  if p.returncode != 0:
+    print(stdout)
+    print(stderr)
+    RequestCipdAuthentication()
+    return 1
 
   # Accept the license for this version of Xcode if it's newer than the
   # currently accepted version.
@@ -177,7 +185,7 @@ def InstallXcodeBinaries():
       should_overwrite_license = False
 
   if not should_overwrite_license:
-    return
+    return 0
 
   # Use puppet's sudoers script to accept the license if its available.
   license_accept_script = '/usr/local/bin/xcode_accept_license.py'
@@ -185,7 +193,7 @@ def InstallXcodeBinaries():
     args = ['sudo', license_accept_script, '--xcode_version',
             cipd_xcode_version, '--license-version', cipd_license_version]
     subprocess.call(args)
-    return
+    return 0
 
   # Otherwise manually accept the license. This will prompt for sudo.
   print('Accepting new Xcode license. Requires sudo.')
@@ -199,6 +207,8 @@ def InstallXcodeBinaries():
   args = ['sudo', 'plutil', '-convert', 'xml1', current_license_path]
   subprocess.call(args)
 
+  return 0
+
 
 def main():
   if sys.platform != 'darwin':
@@ -227,9 +237,7 @@ def main():
   if not success:
     return 1
 
-  InstallXcodeBinaries()
-
-  return 0
+  return InstallXcodeBinaries()
 
 
 if __name__ == '__main__':