Support default values for complex objects in mojom.

mojo/public/bindings/pylib/generate/mojom_generator.py

Index: mojo/public/bindings/pylib/generate/mojom_generator.py
diff --git a/mojo/public/bindings/pylib/generate/mojom_generator.py b/mojo/public/bindings/pylib/generate/mojom_generator.py
index 7e89c03e571c56914f4ad5406c0c2e17a08052bf..e8c0fd5ad68241bc150b2ad8dac2567a7ba8d22d 100644
--- a/mojo/public/bindings/pylib/generate/mojom_generator.py
+++ b/mojo/public/bindings/pylib/generate/mojom_generator.py
@@ -25,6 +25,12 @@ def GetStructInfo(exported, struct):
   struct.exported = exported
   return struct
 
+def GetStructByName(structs, name):
+  for struct in structs:
+    if struct.name == name:
+      return struct
+  return None
+
 def IsStringKind(kind):
   return kind.spec == 's'
 
@@ -41,6 +47,18 @@ def CamelToUnderscores(camel):
 def StudlyCapsToCamel(studly):
   return studly[0].lower() + studly[1:]
 
+def VerifyTokenType(token, expected):
+  """Used to check that arrays and objects are used correctly as default
+  values. Arrays are tokens that look like ('ARRAY', element0, element1...).
+  See mojom_parser.py for their representation.
+  """
+  if not isinstance(token, tuple):
+    raise Exception("Expected token type '%s'. Invalid token '%s'." %
+        (expected, token))
+  if token[0] != expected:
+    raise Exception("Expected token type '%s'. Got '%s'." %
+        (expected, token[0]))
+
 class Generator(object):
   # Pass |output_dir| to emit files to disk. Omit |output_dir| to echo all
   # files to stdout.