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

chrome/browser/browser_process_impl_win.cc

Index: chrome/browser/browser_process_impl_win.cc
diff --git a/chrome/browser/browser_process_impl_win.cc b/chrome/browser/browser_process_impl_win.cc
index 9d013fdbb23ed98e0356988af2a123a98e4aba3c..2e2c0435163c7c3bf70a5866a13e29729d142aef 100644
--- a/chrome/browser/browser_process_impl_win.cc
+++ b/chrome/browser/browser_process_impl_win.cc
@@ -4,10 +4,12 @@
 #include "chrome/browser/browser_process_impl.h"
 
 #include "base/command_line.h"
-#include "chrome/common/chrome_switches.h"
 
 #if defined(USE_AURA)
+#include "base/logging.h"
+#include "base/process_util.h"
 #include "chrome/browser/metro_viewer/metro_viewer_process_host_win.h"
+#include "chrome/common/chrome_switches.h"
 #endif
 
 void BrowserProcessImpl::PlatformSpecificCommandLineProcessing(
@@ -22,6 +24,20 @@ void BrowserProcessImpl::OnMetroViewerProcessTerminated() {
   metro_viewer_process_host_.reset(NULL);
 }
 
+void BrowserProcessImpl::TerminateMetroViewerProcess() {
+  if (metro_viewer_process_host_) {
+    base::ProcessId viewer_id =
+        metro_viewer_process_host_->GetViewerProcessId();
+    if (viewer_id == base::kNullProcessId)
+      return;
+    // The viewer doesn't hold any state so it is fine to kill it before it
+    // cleanly exits. This will trigger MetroViewerProcessHost::OnChannelError()
+    // which will cleanup references to g_browser_process.
+    bool success = base::KillProcessById(viewer_id, 0, true);
+    DCHECK(success);
+  }
+}
+
 void BrowserProcessImpl::PerformInitForWindowsAura(
     const CommandLine& command_line) {
   if (command_line.HasSwitch(switches::kViewerConnection) &&