Move full-screen detection logic from PanelManager to DisplaySettingsProvider.

chrome/browser/ui/panels/display_settings_provider_win.cc

Index: chrome/browser/ui/panels/display_settings_provider_win.cc
diff --git a/chrome/browser/ui/panels/display_settings_provider_win.cc b/chrome/browser/ui/panels/display_settings_provider_win.cc
index f41eda0e7fcb405038b3affc6d559c3d69efe36e..b4c3d299689a59dd293e8c321c2dca3a0c417c97 100644
--- a/chrome/browser/ui/panels/display_settings_provider_win.cc
+++ b/chrome/browser/ui/panels/display_settings_provider_win.cc
@@ -172,9 +172,11 @@ bool DisplaySettingsProviderWin::CheckTaskbars(bool notify_observer) {
         alignment, bounds);
     if (visibility != taskbars_[i].visibility) {
       taskbars_[i].visibility = visibility;
-      if (notify_observer && desktop_bar_observer()) {
-        desktop_bar_observer()->OnAutoHidingDesktopBarVisibilityChanged(
-            alignment, visibility);
+      if (notify_observer) {
+        FOR_EACH_OBSERVER(
+            DesktopBarObserver,
+            desktop_bar_observers(),
+            OnAutoHidingDesktopBarVisibilityChanged(alignment, visibility));
       }
     }
   }