[Closure Externs] Generate closure compiler externs as part of compile

tools/json_schema_compiler/compiler.py

Index: tools/json_schema_compiler/compiler.py
diff --git a/tools/json_schema_compiler/compiler.py b/tools/json_schema_compiler/compiler.py
index c626f2f96c20570980c9b2637dcdae96c5128271..43aa45bb5f5e387169248db363bc59b4103ecb3f 100755
--- a/tools/json_schema_compiler/compiler.py
+++ b/tools/json_schema_compiler/compiler.py
@@ -44,7 +44,8 @@ def GenerateSchema(generator_name,
                    cpp_namespace_pattern,
                    bundle_name,
                    impl_dir,
-                   include_rules):
+                   include_rules,
+                   custom_output_dir):
   # Merge the source files into a single list of schemas.
   api_defs = []
   for file_path in file_paths:
@@ -126,8 +127,9 @@ def GenerateSchema(generator_name,
       ('%s.cc' % filename_base, cpp_generator.cc_generator)
     ]
   elif generator_name == 'externs':
+    print('Generating js externs')
     generators = [
-      ('%s_externs.js' % namespace.unix_name, JsExternsGenerator())
+      ('%s.js' % namespace.unix_name, JsExternsGenerator())
     ]
   elif generator_name == 'interface':
     generators = [
@@ -145,7 +147,8 @@ def GenerateSchema(generator_name,
         # API implementations.
         output_dir = os.path.join(destdir, impl_dir)
       else:
-        output_dir = os.path.join(destdir, src_path)
+        path = custom_output_dir if custom_output_dir else src_path
+        output_dir = os.path.join(destdir, path)
       if not os.path.exists(output_dir):
         os.makedirs(output_dir)
       with open(os.path.join(output_dir, filename), 'w') as f:
@@ -184,6 +187,9 @@ if __name__ == '__main__':
       help='A list of paths to include when searching for referenced objects,'
       ' with the namespace separated by a \':\'. Example: '
       '/foo/bar:Foo::Bar::%(namespace)s')
+  parser.add_option('-o', '--output-dir',
+      help='A custom output directory under the "gen" folder. If not provided,'
+      ' this defaults to the source path.')
 
   (opts, file_paths) = parser.parse_args()
 
@@ -210,6 +216,6 @@ if __name__ == '__main__':
 
   result = GenerateSchema(opts.generator, file_paths, opts.root, opts.destdir,
                           opts.namespace, opts.bundle_name, opts.impl_dir,
-                          include_rules)
+                          include_rules, opts.output_dir)
   if not opts.destdir:
     print result