Shell: Remove the test child stuff.

shell/app_child_process.cc

Index: shell/app_child_process.cc
diff --git a/shell/app_child_process.cc b/shell/app_child_process.cc
index 1e99dc3f43ac37ac1e11ec6bca64f221a889447b..18cf1d8b5a3b091d2f3cfb6271d9a464757e574d 100644
--- a/shell/app_child_process.cc
+++ b/shell/app_child_process.cc
@@ -224,6 +224,11 @@ class AppChildControllerImpl : public AppChildController, public ErrorHandler {
                                   base::Passed(&application_request)));
   }
 
+  void ExitNow(int32_t exit_code) override {
+    DVLOG(2) << "AppChildControllerImpl::ExitNow(" << exit_code << ")";
+    _exit(exit_code);
+  }
+
  private:
   AppChildControllerImpl(AppContext* app_context,
                          const Blocker::Unblocker& unblocker)
@@ -279,6 +284,8 @@ AppChildProcess::~AppChildProcess() {
 void AppChildProcess::Main() {
   DVLOG(2) << "AppChildProcess::Main()";
 
+  DCHECK(!base::MessageLoop::current());
+
   AppContext app_context;
   app_context.Init();