Less attempted magic in pulling toolchain

- Don't try to wrap download_from_google_storage --config, instead just
request that the user runs it manually. (This is annoying either way
but making it magically run makes it less clear what's going on, and so
harder to debug when something goes wrong, per linked bug).

- Check that SHA1s are passed as expected on the command line in case
the script is run directly, rather than from gyp_chromium.

R=scherkus@chromium.org
BUG=349596

Review URL: https://codereview.chromium.org/189093017

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@256049 0039d316-1c4b-4281-b951-d872f2087c98

win_toolchain/get_toolchain_if_necessary.py

@@ -147,31 +147,28 @@ def CanAccessToolchainBucket():
   return code == 0
 
 
-def ConfigureGsAccess():
-  """Starts the authentication flow for gs://, and confirms that it's
-  accessible after completion, or retries indefinitely.
+def RequestGsAuthentication():
+  """Requests that the user authenticate to be able to access gs:// as a
+  Googler. This allows much faster downloads, and pulling (old) toolchains
+  that match src/ revisions.
   """
-  while not CanAccessToolchainBucket():
   print 'Access to gs://chrome-wintoolchain/ not configured.'
   print '-----------------------------------------------------------------'
   print
   print 'You appear to be a Googler.'
   print
   print 'I\'m sorry for the hassle, but you need to do a one-time manual'
-    print 'authentication. Instructions will open in a new window. This is'
-    print 'a run of "gsutil config".'
+  print 'authentication. Please run:'
   print
-    print 'NOTE: Just press Enter when asked for a "project-id".'
+  print '    download_from_google_storage --config'
+  print
+  print 'and follow the instructions. NOTE: Just press Enter when asked for'
+  print 'a "project-id".'
   print
   print '-----------------------------------------------------------------'
   print
   sys.stdout.flush()
-    # gclient's buffering makes this hang if we're run from inside gclient
-    # as is typical. So, spawn a new window for the config prompt. :(
-    subprocess.check_call(
-        ['start', '/wait', 'cmd', '/c',
-         'download_from_google_storage', '--config'],
-        shell=True)
+  sys.exit(1)
 
 
 def DelayBeforeRemoving(target_dir):
@@ -197,6 +194,8 @@ def main():
 
   # We assume that the Pro hash is the first one.
   desired_hashes = args
+  if len(desired_hashes) == 0:
+    sys.exit('Desired hashes are required.')
 
   # Move to depot_tools\win_toolchain where we'll store our files, and where
   # the downloader script is.
@@ -211,11 +210,10 @@ def main():
   current_hash = CalculateHash(target_dir)
   if current_hash not in desired_hashes:
     should_use_gs = False
-    if (CanAccessToolchainBucket() or
-        HaveSrcInternalAccess() or
-        LooksLikeGoogler()):
+    if HaveSrcInternalAccess() or LooksLikeGoogler():
       should_use_gs = True
-      ConfigureGsAccess()
+      if not CanAccessToolchainBucket():
+        RequestGsAuthentication()
     print('Windows toolchain out of date or doesn\'t exist, updating (%s)...' %
           ('Pro' if should_use_gs else 'Express'))
     print('  current_hash: %s' % current_hash)