Shell: Remove the test child stuff.

shell/app_child_process_host.cc

Index: shell/app_child_process_host.cc
diff --git a/shell/app_child_process_host.cc b/shell/app_child_process_host.cc
index d96a33b53528a0a8f8ab35c6f56060df2f7ce7e3..3b1eaf0960e9970614674dbdd3f2581bf0d82adb 100644
--- a/shell/app_child_process_host.cc
+++ b/shell/app_child_process_host.cc
@@ -36,6 +36,12 @@ void AppChildProcessHost::StartApp(
       base::Bind(&AppChildProcessHost::AppCompleted, base::Unretained(this)));
 }
 
+void AppChildProcessHost::ExitNow(int32_t exit_code) {
+  DCHECK(controller_);
+
+  controller_->ExitNow(exit_code);
+}
+
 void AppChildProcessHost::WillStart() {
   DCHECK(platform_channel()->is_valid());