Revert "Generate some of the C++ bindings for mojom tagged unions."

mojo/public/tools/bindings/pylib/mojom/generate/module.py

Index: mojo/public/tools/bindings/pylib/mojom/generate/module.py
diff --git a/mojo/public/tools/bindings/pylib/mojom/generate/module.py b/mojo/public/tools/bindings/pylib/mojom/generate/module.py
index bfa5863b340a533ba2070f8add496bc8b3f71de0..8e52924f27d22cd2615559c29542691301384950 100644
--- a/mojo/public/tools/bindings/pylib/mojom/generate/module.py
+++ b/mojo/public/tools/bindings/pylib/mojom/generate/module.py
@@ -422,10 +422,6 @@ def IsStructKind(kind):
   return isinstance(kind, Struct)
 
 
-def IsUnionKind(kind):
-  return isinstance(kind, Union)
-
-
 def IsArrayKind(kind):
   return isinstance(kind, Array)
 
@@ -456,7 +452,7 @@ def IsMapKind(kind):
 
 def IsObjectKind(kind):
   return (IsStructKind(kind) or IsArrayKind(kind) or IsStringKind(kind) or
-          IsMapKind(kind) or IsUnionKind(kind))
+          IsMapKind(kind))
 
 
 def IsNonInterfaceHandleKind(kind):
@@ -487,7 +483,7 @@ def IsCloneableKind(kind):
       return True
     if IsArrayKind(kind):
       return ContainsHandles(kind.kind, visited_kinds)
-    if IsStructKind(kind) or IsUnionKind(kind):
+    if IsStructKind(kind):
       for field in kind.fields:
         if ContainsHandles(field.kind, visited_kinds):
           return True