Reinstate wait-for-Initialize when Chrome is run in Mash

chrome/app/mash/mash_runner.cc

Index: chrome/app/mash/mash_runner.cc
diff --git a/chrome/app/mash/mash_runner.cc b/chrome/app/mash/mash_runner.cc
index 839857d61c33b31ad80d3c544faa3c3c1b09e831..61d0756da17b1a5c437715a3e849ada619eb7841 100644
--- a/chrome/app/mash/mash_runner.cc
+++ b/chrome/app/mash/mash_runner.cc
@@ -138,6 +138,7 @@ class NativeRunnerDelegateImpl : public mojo::shell::NativeRunnerDelegate {
   void AdjustCommandLineArgumentsForTarget(
       const mojo::Identity& target,
       base::CommandLine* command_line) override {
+    command_line->AppendSwitch(switches::kWaitForMojoShell);
     if (target.name() != "exe:chrome") {
       if (target.name() == "exe:chrome_mash")
         ChangeChromeMashToChrome(command_line);