In WinAura, also kill the Metro viewer process in AttemptExit().

chrome/browser/metro_viewer/metro_viewer_process_host_win.cc

Index: chrome/browser/metro_viewer/metro_viewer_process_host_win.cc
diff --git a/chrome/browser/metro_viewer/metro_viewer_process_host_win.cc b/chrome/browser/metro_viewer/metro_viewer_process_host_win.cc
index 806d29c33ad46ecd82b12b3730f7c077375f3d9e..813bf73a97ed91de3231688b5857c4da594a3fce 100644
--- a/chrome/browser/metro_viewer/metro_viewer_process_host_win.cc
+++ b/chrome/browser/metro_viewer/metro_viewer_process_host_win.cc
@@ -54,6 +54,13 @@ MetroViewerProcessHost::MetroViewerProcessHost(
 MetroViewerProcessHost::~MetroViewerProcessHost() {
 }
 
+base::ProcessId MetroViewerProcessHost::GetViewerProcessId() {
+  if (channel_)
+    return channel_->peer_pid();
+  else
+    return base::kNullProcessId;
+}
+
 bool MetroViewerProcessHost::Send(IPC::Message* msg) {
   return channel_->Send(msg);
 }