Allow mojo sync calls in single-process mode

content/browser/browser_main_loop.cc

 // Copyright (c) 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.
 
 #include "content/browser/browser_main_loop.h"
 
 #include <stddef.h>
 
 #include <string>
 #include <utility>
@@ skipping 1144 matching lines @@
   // Register the main thread by instantiating it, but don't call any methods.
   main_thread_.reset(
       new BrowserThreadImpl(BrowserThread::UI, base::MessageLoop::current()));
 }
 
 int BrowserMainLoop::BrowserThreadsStarted() {
   TRACE_EVENT0("startup", "BrowserMainLoop::BrowserThreadsStarted");
 
   // Bring up Mojo IPC and shell as early as possible.
 
-  // Disallow mojo sync call in the browser process.
-  bool sync_call_allowed = false;
-  MojoResult result = mojo::edk::SetProperty(
-      MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED, &sync_call_allowed);
-  DCHECK_EQ(MOJO_RESULT_OK, result);
+  if (!parsed_command_line_.HasSwitch(switches::kSingleProcess)) {
+    // Disallow mojo sync calls in the browser process. Note that we allow sync
+    // calls in single-process mode since renderer IPCs are made from a browser
+    // thread.
+    bool sync_call_allowed = false;
+    MojoResult result = mojo::edk::SetProperty(
+        MOJO_PROPERTY_TYPE_SYNC_CALL_ALLOWED, &sync_call_allowed);
+    DCHECK_EQ(MOJO_RESULT_OK, result);
+  }
 
   mojo_ipc_support_.reset(new mojo::edk::ScopedIPCSupport(
       BrowserThread::UnsafeGetMessageLoopForThread(BrowserThread::IO)
           ->task_runner()));
 
   mojo_shell_context_.reset(new MojoShellContext);
   if (shell::ShellIsRemote()) {
 #if defined(MOJO_SHELL_CLIENT) && defined(USE_AURA)
     // TODO(rockot): Remove the blocking wait for init.
     // http://crbug.com/594852.
@@ skipping 337 matching lines @@
                                                  std::move(worker_task_runner),
                                                  MediaInternals::GetInstance());
   }
   CHECK(audio_manager_);
 
   if (use_hang_monitor)
     media::AudioManager::StartHangMonitor(io_thread_->task_runner());
 }
 
 }  // namespace content