Add visibility restrictions to all mojoms that export symbols.

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.
 
 mojom_generator_root = "//mojo/public/tools/bindings"
 mojom_generator_script = "$mojom_generator_root/mojom_bindings_generator.py"
 mojom_generator_sources = [
   "$mojom_generator_root/generators/mojom_cpp_generator.py",
   "$mojom_generator_root/generators/mojom_js_generator.py",
   "$mojom_generator_root/generators/mojom_java_generator.py",
@@ skipping 69 matching lines @@
 #   public_deps (optional)
 #       Note: this can contain only other mojom targets.
 #
 #   import_dirs (optional)
 #       List of import directories that will get added when processing sources.
 #
 #   testonly (optional)
 #
 #   visibility (optional)
 #
+#   visibility_blink (optional)
+#       The value to use for visibility for the blink variant. If unset,
+#       |visibility| is used.
+#
 #   use_once_callback (optional)
 #       If set to true, generated classes will use base::OnceCallback instead of
 #       base::RepeatingCallback.
 #       Default value is false.
 #       TODO(dcheng):
 #           - Convert everything to use OnceCallback.
 #           - Remove support for the old mode.
 #
 #   cpp_only (optional)
 #       If set to true, only the C++ bindings targets will be generated.
@@ skipping 328 matching lines @@
           }
           foreach(value, typemap.type_mappings) {
             typemap_description += [ "type_mappings=$value" ]
           }
         }
         args += typemap_description
       }
     }
 
     source_set("${target_name}${variant_suffix}") {
-      if (defined(invoker.visibility)) {
+      if (defined(bindings_configuration.for_blink) &&
+          bindings_configuration.for_blink &&
+          defined(invoker.visibility_blink)) {
+        visibility = invoker.visibility_blink
+      } else if (defined(invoker.visibility)) {
         visibility = invoker.visibility
       }
       if (defined(invoker.testonly)) {
         testonly = invoker.testonly
       }
       if (defined(invoker.sources) && !defined(bindings_configuration.variant)) {
         data = process_file_template(enabled_sources, generator_js_outputs)
       }
       defines = []
       if (defined(invoker.testonly)) {
@@ skipping 119 matching lines @@
           full_name = get_label_info(d, "label_no_toolchain")
           deps += [ "${full_name}_java" ]
         }
 
         srcjar_deps = [ ":$java_srcjar_target_name" ]
         run_findbugs_override = false
       }
     }
   }
 }