Add a switch in BUILD rules to control the generation of type info for mojom files.

mojo/public/tools/bindings/mojom.gni

 # Copyright 2014 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.
 
 import("../../mojo_sdk.gni")
 
 # TODO(azani): Remove when the switch to the new compiler is complete.
 declare_args() {
   use_old_mojom_compiler = false
 }
@@ skipping 187 matching lines @@
         "-o",
         rebase_path(root_gen_dir),
         "--no-gen-imports",
       ]
 
       # TODO(azani): Remove when the switch to the new compiler is complete.
       if (use_old_mojom_compiler) {
         args += [ "--compiler-version=1" ]
       }
 
+      if (defined(invoker.generate_type_info) && invoker.generate_type_info) {
+        args += [ "--generate-type-info" ]
+      } else {
+        args += [ "--no-generate-type-info" ]
+      }
+
       if (defined(invoker.import_dirs)) {
         foreach(import_dir, invoker.import_dirs) {
           args += [
             "-I",
             rebase_path(import_dir, root_build_dir),
           ]
         }
       }
     }
   }
@@ skipping 194 matching lines @@
         # //mojo/something:something and we can append "_java" to get the java
         # dependency name.
         full_name = get_label_info(d, "label_no_toolchain")
         deps += [ "${full_name}_java" ]
       }
 
       srcjar_deps = [ ":$java_srcjar_target_name" ]
     }
   }
 }