headless: Fix inconsistent header naming

headless/lib/browser/devtools_api/client_api_generator.py

Index: headless/lib/browser/devtools_api/client_api_generator.py
diff --git a/headless/lib/browser/devtools_api/client_api_generator.py b/headless/lib/browser/devtools_api/client_api_generator.py
index ce96de211b4a60c20f4b32f540fc57552188bdd2..435358af73da43c8c409fb8bbaee92c1f3ab51d3 100644
--- a/headless/lib/browser/devtools_api/client_api_generator.py
+++ b/headless/lib/browser/devtools_api/client_api_generator.py
@@ -494,8 +494,8 @@ def GenerateTypes(jinja_env, output_dirname, json_api):
   # Generate forward declarations for types.
   GeneratePerDomain(
       jinja_env, os.path.join(output_dirname, 'devtools', 'internal'),
-      json_api, 'domain_types_forward_declaration', ['h'],
-      lambda domain_name: 'types_forward_declaration_%s' % (domain_name, ))
+      json_api, 'domain_types_forward_declarations', ['h'],
+      lambda domain_name: 'types_forward_declarations_%s' % (domain_name, ))
   # Generate types on per-domain basis.
   GeneratePerDomain(
       jinja_env, os.path.join(output_dirname, 'devtools', 'domains'),