Check NaCl debug mask (not just flag) before choosing PNaCl debug URL.

components/nacl/common/nacl_host_messages.h

 // Copyright 2013 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.
 
 // Multiply-included file, no traditional include guard.
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/process/process.h"
@@ skipping 86 matching lines @@
 
 // A renderer sends this to the browser process when it wants to
 // open a NaCl executable file from an installed application directory.
 IPC_SYNC_MESSAGE_CONTROL2_3(NaClHostMsg_OpenNaClExecutable,
                             int /* render_view_id */,
                             GURL /* URL of NaCl executable file */,
                             IPC::PlatformFileForTransit /* output file */,
                             uint64 /* file_token_lo */,
                             uint64 /* file_token_hi */)
 
+// A renderer sends this to the browser process to determine how many
+// processors are online.
 IPC_SYNC_MESSAGE_CONTROL0_1(NaClHostMsg_NaClGetNumProcessors,
                             int /* Number of processors */)
+
+// A renderer sends this to the browser process to determine if the
+// NaCl application started from the given NMF URL will be debugged.
+// If not (filtered out by commandline flags), it sets should_debug to false.
+IPC_SYNC_MESSAGE_CONTROL1_1(NaClHostMsg_NaClDebugEnabledForURL,
+                            GURL /* alleged URL of NMF file */,
+                            bool /* should debug */)