mustash: enable GPU Compositing in renderer

content/browser/renderer_host/render_process_host_impl.cc

Index: content/browser/renderer_host/render_process_host_impl.cc
diff --git a/content/browser/renderer_host/render_process_host_impl.cc b/content/browser/renderer_host/render_process_host_impl.cc
index 8834c0d31242f7b710ed928c71d54df267e86a97..0301041436eaf306c3b84480be423c751b1ef930 100644
--- a/content/browser/renderer_host/render_process_host_impl.cc
+++ b/content/browser/renderer_host/render_process_host_impl.cc
@@ -224,6 +224,7 @@
 
 #if defined(MOJO_SHELL_CLIENT)
 #include "content/browser/mojo/mojo_shell_client_host.h"
+#include "content/common/mojo/mojo_shell_connection_impl.h"
 #endif
 
 #if defined(OS_WIN)
@@ -1544,6 +1545,11 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
       renderer_cmd->AppendSwitch(switches::kWaitForDebugger);
     }
   }
+
+#if defined(MOJO_SHELL_CLIENT)
+  if (IsRunningInMojoShell())
+    renderer_cmd->AppendSwitch(switches::kEnableMojoShellConnection);
+#endif
 }
 
 base::ProcessHandle RenderProcessHostImpl::GetHandle() const {