mus: Make --use-mus-in-renderer the default for --mash.

content/browser/renderer_host/render_process_host_impl.cc

 // Copyright 2012 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.
 
 // Represents the browser side of the browser <--> renderer communication
 // channel. There will be one RenderProcessHost per renderer process.
 
 #include "content/browser/renderer_host/render_process_host_impl.h"
 
 #include <algorithm>
@@ skipping 1858 matching lines @@
 #if defined(USE_OZONE)
     switches::kOzonePlatform,
 #endif
 #if defined(OS_CHROMEOS)
     switches::kDisableVaapiAcceleratedVideoEncode,
 #endif
 #if defined(ENABLE_IPC_FUZZER)
     switches::kIpcDumpDirectory,
     switches::kIpcFuzzerTestcase,
 #endif
-    switches::kUseMusInRenderer,
+    switches::kNoUseMusInRenderer,

[jam, 2017/01/31 16:06:50]

nit: pattern here is to put switches not in ifdef sorted above, then end with
ifdefs. so move this up

[sadrul, 2017/01/31 17:01:04]

Done.

   };
   renderer_cmd->CopySwitchesFrom(browser_cmd, kSwitchNames,
                                  arraysize(kSwitchNames));
 
   BrowserChildProcessHostImpl::CopyFeatureAndFieldTrialFlags(renderer_cmd);
 
   if (browser_cmd.HasSwitch(switches::kTraceStartup) &&
       BrowserMainLoop::GetInstance()->is_tracing_startup_for_duration()) {
     // Pass kTraceStartup switch to renderer only if startup tracing has not
     // finished.
@@ skipping 1166 matching lines @@
   LOG(ERROR) << "Terminating render process for bad Mojo message: " << error;
 
   // The ReceivedBadMessage call below will trigger a DumpWithoutCrashing.
   // Capture the error message in a crash key value.
   base::debug::ScopedCrashKey error_key_value("mojo-message-error", error);
   bad_message::ReceivedBadMessage(render_process_id,
                                   bad_message::RPH_MOJO_PROCESS_ERROR);
 }
 
 }  // namespace content