Allow mojo sync calls in single-process mode

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 73ea7767ba632f9c0822e45f6775936abbcc2c75..4fa4dcd75948867bcbc0e3e945245f52c02bc416 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -1162,11 +1162,15 @@ int 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)