cros: Add CHECK for screen unlock problem

On some devices when you unlock the screen after suspend the launcher and
desktop windows do not appear. I suspect the background widget is not being
reparented properly but I cannot reproduce the problem internally.  Since
the user can't recover from this state without rebooting, add some CHECKs
to try to track down the source.

Also initialize empty wallpaper if we're running tests, as we previously
skipped it which would cause my CHECKs to be hit.

BUG=149043
TEST=ScreenLockerTest and manual, lock screen with Ctrl-Shift-L, unlock by entering password


Review URL: https://chromiumcodereview.appspot.com/10982035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@158846 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 8 insertions, 0 deletions

diff --git a/ash/desktop_background/desktop_background_controller.cc b/ash/desktop_background/desktop_background_controller.cc
index cb186ad..51bb338 100644
--- a/ash/desktop_background/desktop_background_controller.cc
+++ b/ash/desktop_background/desktop_background_controller.cc
@@ -347,6 +347,7 @@ void DesktopBackgroundController::InstallComponentForAllWindows() {
 
 void DesktopBackgroundController::ReparentBackgroundWidgets(int src_container,
                                                             int dst_container) {
+  bool reparented = false;
   Shell::RootWindowList root_windows = Shell::GetAllRootWindows();
   for (Shell::RootWindowList::iterator iter = root_windows.begin();
     iter != root_windows.end(); ++iter) {
@@ -364,8 +365,15 @@ void DesktopBackgroundController::ReparentBackgroundWidgets(int src_container,
       component->Reparent(root_window,
                           src_container,
                           dst_container);
+      reparented = true;
     }
   }
+  // If we didn't reparent the desktop background then either the screen is
+  // unlocked and the user's windows are hidden, or the screen is locked and
+  // the user's windows are visible. Either case is bad, and the first case
+  // is happening in the field.  Check if this location is the cause.
+  // See crbug.com/149043
+  CHECK(reparented);
 }
 
 int DesktopBackgroundController::GetBackgroundContainerId(bool locked) {