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

mojo/edk/system/core.cc

Index: mojo/edk/system/core.cc
diff --git a/mojo/edk/system/core.cc b/mojo/edk/system/core.cc
index d8d861aee90a390bbe738b2a0b01fc599f6d7ac2..aca5b25967374ef6d2b3196ba173ec32cbfbdb3c 100644
--- a/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -377,6 +377,17 @@ MojoResult Core::AsyncWait(MojoHandle handle,
   return rv;
 }
 
+MojoResult Core::SetProperty(MojoPropertyType type, const void* value) {
+  base::AutoLock locker(property_lock_);
+  switch (type) {
+    case MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED:
+      property_sync_call_allowed_ = *static_cast<const bool*>(value);
+      return MOJO_RESULT_OK;
+    default:
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+}
+
 MojoTimeTicks Core::GetTimeTicksNow() {
   return base::TimeTicks::Now().ToInternalValue();
 }
@@ -526,6 +537,17 @@ MojoResult Core::GetMessageBuffer(MojoMessageHandle message, void** buffer) {
   return MOJO_RESULT_OK;
 }
 
+MojoResult Core::GetProperty(MojoPropertyType type, void* value) {
+  base::AutoLock locker(property_lock_);
+  switch (type) {
+    case MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED:
+      *static_cast<bool*>(value) = property_sync_call_allowed_;
+      return MOJO_RESULT_OK;
+    default:
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+}
+
 MojoResult Core::CreateWaitSet(MojoHandle* wait_set_handle) {
   RequestContext request_context;
   if (!wait_set_handle)