git-sync-deps: handle recursion and deps_os at the same time

tools/git-sync-deps

Index: tools/git-sync-deps
diff --git a/tools/git-sync-deps b/tools/git-sync-deps
index 717ab38055287dc2af9a0bdb4c814fcdca51fb79..4a0ded1f828d7299be914a1563ebca86dd2816ce 100755
--- a/tools/git-sync-deps
+++ b/tools/git-sync-deps
@@ -154,7 +154,7 @@ class DepsError(Exception):
   pass
 
 
-def git_sync_deps(deps_file_path, deps_os_list, verbose):
+def git_sync_deps(deps_file_path, command_line_os_requests, verbose):
   """Grab dependencies, with optional platform support.
 
   Args:
@@ -170,16 +170,13 @@ def git_sync_deps(deps_file_path, deps_os_list, verbose):
   assert git
 
   deps_file_directory = os.path.dirname(deps_file_path)
-  deps = parse_file_to_dict(deps_file_path)
-  dependencies = deps['deps'].copy()
-  for deps_os in deps_os_list:
+  deps_file = parse_file_to_dict(deps_file_path)
+  dependencies = deps_file['deps'].copy()
+  os_specific_dependencies = deps_file.get('deps_os', [])
+  for os_name in command_line_os_requests:
     # Add OS-specific dependencies
-    if deps_os not in deps['deps_os']:
-      raise DepsError(
-        'Argument "%s" not found within deps_os keys %r' %
-        (deps_os, deps['deps_os'].keys()))
-    for dep in deps['deps_os'][deps_os]:
-      dependencies[dep] = deps['deps_os'][deps_os][dep]
+    if os_name in os_specific_dependencies:
+      dependencies.update(os_specific_dependencies[os_name])
   list_of_arg_lists = []
   for directory in dependencies:
     if '@' in dependencies[directory]:
@@ -194,9 +191,9 @@ def git_sync_deps(deps_file_path, deps_os_list, verbose):
 
   multithread(git_checkout_to_directory, list_of_arg_lists)
 
-  for directory in deps.get('recursedeps', []):
+  for directory in deps_file.get('recursedeps', []):
     recursive_path = os.path.join(deps_file_directory, directory, 'DEPS')
-    git_sync_deps(recursive_path, deps_os_list, verbose)
+    git_sync_deps(recursive_path, command_line_os_requests, verbose)
 
 
 def multithread(function, list_of_arg_lists):