Mojo: add support for disallowing sync calls for a process.

mojo/public/c/system/types.h

 // 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.
 
 // This file contains types and constants/macros common to different Mojo system
 // APIs.
 //
 // Note: This header should be compilable as C.
 
 #ifndef MOJO_PUBLIC_C_SYSTEM_TYPES_H_
@@ skipping 184 matching lines @@
 #ifdef __cplusplus
 const MojoWatchNotificationFlags MOJO_WATCH_NOTIFICATION_FLAG_NONE = 0;
 const MojoWatchNotificationFlags MOJO_WATCH_NOTIFICATION_FLAG_FROM_SYSTEM =
     1 << 0;
 #else
 #define MOJO_WATCH_NOTIFICATION_FLAG_NONE ((MojoWatchNotificationFlags)0)
 #define MOJO_WATCH_NOTIFICATION_FLAG_FROM_SYSTEM \
     ((MojoWatchNotificationFlags)1 << 0);
 #endif
 
+// |MojoPropertyType|: Property types that can be passed to |MojoGetProperty()|
+// to retrieve system properties. May take the following values:
+//   |MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED| - Whether making synchronous calls
+//       (i.e., blocking to wait for a response to an outbound message) is
+//       allowed. The property value is of boolean type. If the value is true,
+//       users should refrain from making sync calls.
+typedef uint32_t MojoPropertyType;
+
+#ifdef __cplusplus
+const MojoPropertyType MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED = 0;
+#else
+#define MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED ((MojoPropertyType)0)
+#endif
+
 #endif  // MOJO_PUBLIC_C_SYSTEM_TYPES_H_