Make the root_namespace argument to json_schema_compiler.gypi a string

tools/json_schema_compiler/cpp_generator.py

Index: tools/json_schema_compiler/cpp_generator.py
diff --git a/tools/json_schema_compiler/cpp_generator.py b/tools/json_schema_compiler/cpp_generator.py
index b765229e500aa145ea17eb7c54098ed294ec0738..7441ac5eaf1bde057349c6000eba7a28c9e11e6e 100644
--- a/tools/json_schema_compiler/cpp_generator.py
+++ b/tools/json_schema_compiler/cpp_generator.py
@@ -6,6 +6,6 @@ from cc_generator import CCGenerator
 from h_generator import HGenerator
 
 class CppGenerator(object):
-  def __init__(self, type_generator, cpp_namespace):
-    self.h_generator = HGenerator(type_generator, cpp_namespace)
-    self.cc_generator = CCGenerator(type_generator, cpp_namespace)
+  def __init__(self, type_generator, cpp_namespace_pattern):
+    self.h_generator = HGenerator(type_generator, cpp_namespace_pattern)
+    self.cc_generator = CCGenerator(type_generator, cpp_namespace_pattern)