Generate all extension schema namespaces as "api" and instead vary the generated bundle names.

build/json_schema_bundle_compile.gypi

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     # When including this gypi, the following variables must be set:
     #   schema_files:
     #     An array of json or idl files that comprise the api model.
     #   schema_include_rules (optional):
     #     An array of paths to include when searching for referenced objects,
     #     with the namespace separated by a :.
     #     Example:
     #       [ '/foo/bar:Foo::Bar::%(namespace)s' ]
     #   cc_dir:
     #     The directory to put the generated code in.
     #   root_namespace:
     #     A Python string substituion pattern used to generate the C++
     #     namespace for each API. Use %(namespace)s to replace with the API
     #     namespace, like "toplevel::%(namespace)s_api".
+    #   bundle_name:
+    #     A string to prepend to generated bundle class names, so that multiple
+    #     bundle rules can be used without conflicting.  Only used with one of
+    #     the cpp-bundle generators.
     #
     # Functions and namespaces can be excluded by setting "nocompile" to true.
     # The default root path of API implementation sources is
     # chrome/browser/extensions/api and can be overridden by setting "impl_dir".
     'api_gen_dir': '<(DEPTH)/tools/json_schema_compiler',
     'api_gen': '<(api_gen_dir)/compiler.py',
     'generator_files': [
       '<(api_gen_dir)/cc_generator.py',
       '<(api_gen_dir)/code.py',
       '<(api_gen_dir)/compiler.py',
@@ skipping 19 matching lines @@
       'outputs': [
         '<(SHARED_INTERMEDIATE_DIR)/<(cc_dir)/generated_schemas.h',
         '<(SHARED_INTERMEDIATE_DIR)/<(cc_dir)/generated_schemas.cc',
       ],
       'action': [
         'python',
         '<(api_gen)',
         '--root=<(DEPTH)',
         '--destdir=<(SHARED_INTERMEDIATE_DIR)',
         '--namespace=<(root_namespace)',
+        '--bundle-name=<(bundle_name)',
         '--generator=cpp-bundle-schema',
         '--include-rules=<(schema_include_rules)',
         '<@(schema_files)',
         '<@(non_compiled_schema_files)',
       ],
       'message': 'Generating C++ API bundle code for schemas',
       'process_outputs_as_sources': 1,
       # Avoid running MIDL compiler on IDL input files.
       'explicit_idl_action': 1,
     },
   ],
   'include_dirs': [
     '<(SHARED_INTERMEDIATE_DIR)',
     '<(DEPTH)',
   ],
   'direct_dependent_settings': {
     'include_dirs': [
       '<(SHARED_INTERMEDIATE_DIR)',
     ]
   },
   # This target exports a hard dependency because it generates header
   # files.
   'hard_dependency': 1,
 }