Revert of Move content's shell connections to the IO thread

content/browser/gpu/gpu_process_host.cc

Index: content/browser/gpu/gpu_process_host.cc
diff --git a/content/browser/gpu/gpu_process_host.cc b/content/browser/gpu/gpu_process_host.cc
index ff47de955c4d71c4347c933c63edf7a846e6d53b..8c3a201cc673bc620b7a84c66dc58eebcfd58c06 100644
--- a/content/browser/gpu/gpu_process_host.cc
+++ b/content/browser/gpu/gpu_process_host.cc
@@ -565,9 +565,10 @@
 
   DCHECK(!mojo_child_connection_);
   mojo_child_connection_.reset(new MojoChildConnection(
-      kGpuMojoApplicationName, "", child_token_,
-      MojoShellContext::GetConnectorForIOThread(),
-      BrowserThread::GetTaskRunnerForThread(BrowserThread::IO)));
+      kGpuMojoApplicationName,
+      "",
+      child_token_,
+      MojoShellContext::GetConnectorForIOThread()));
 
   gpu::GpuPreferences gpu_preferences = GetGpuPreferencesFromCommandLine();
   if (in_process_) {
@@ -938,11 +939,11 @@
 }
 
 shell::InterfaceRegistry* GpuProcessHost::GetInterfaceRegistry() {
-  return mojo_child_connection_->GetInterfaceRegistry();
+  return mojo_child_connection_->connection()->GetInterfaceRegistry();
 }
 
 shell::InterfaceProvider* GpuProcessHost::GetRemoteInterfaces() {
-  return mojo_child_connection_->GetRemoteInterfaces();
+  return mojo_child_connection_->connection()->GetRemoteInterfaces();
 }
 
 GpuProcessHost::GpuProcessKind GpuProcessHost::kind() {