NaCl: create a separate namespace for Mojo handles.

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 80c3d367ba16858731d2c0527c4c073a7faee245..887a9a7fdc32e1ae66fd0f703a7a9d9fce9c1896 100644
--- a/mojo/edk/system/core.cc
+++ b/mojo/edk/system/core.cc
@@ -97,6 +97,15 @@ scoped_refptr<Dispatcher> Core::GetDispatcher(MojoHandle handle) {
   return handle_table_.GetDispatcher(handle);
 }
 
+MojoResult Core::GetAndRemoveDispatcher(MojoHandle handle,
+                                        scoped_refptr<Dispatcher>* dispatcher) {
+  if (handle == MOJO_HANDLE_INVALID)
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  base::AutoLock locker(handle_table_lock_);
+  return handle_table_.GetAndRemoveDispatcher(handle, dispatcher);
+}
+
 MojoResult Core::AsyncWait(MojoHandle handle,
                            MojoHandleSignals signals,
                            const base::Callback<void(MojoResult)>& callback) {