Ensure that on Windows 7, relaunching the browser via chrome://restart or changing about:flags relaunches into Chrome OS mode.

There were two problems here.
1. The viewer process on Windows 7 would not die : Fixed by destroying the window when we get a
   signal from the browser process that the viewer needs to die.

2. Relaunching on Windows 7 would relaunch the existing browser process with the same command line.
   On Windows 8 relaunch launches back into Windows 8 mode as delegate execute has code to launch back
   into the previous mode. On Windows 7 we don't have that luxury. The current approach is to detect
   that we are in Windows 7 in a browser launched to service the viewer process and return that we
   need to launch into Chrome OS mode. Additionally we set the corresponding pref to ensure that
   this is honored.

BUG=413101

Review URL: https://codereview.chromium.org/568623002

Cr-Commit-Position: refs/heads/master@{#294721}

1 files changed, 3 insertions, 0 deletions

diff --git a/win8/metro_driver/chrome_app_view_ash.cc b/win8/metro_driver/chrome_app_view_ash.cc
index 2f615d3..0d1ea8b 100644
--- a/win8/metro_driver/chrome_app_view_ash.cc
+++ b/win8/metro_driver/chrome_app_view_ash.cc
@@ -971,6 +971,9 @@ void ChromeAppViewAsh::OnMetroExit(MetroTerminateMethod method) {
     if (ui_channel_)
       ui_channel_->Close();
 
+    HWND core_window = core_window_hwnd();
+    ::PostMessage(core_window, WM_CLOSE, 0, 0);
+
     globals.app_exit->Exit();
   }
 }