Have panels respond to changes in work area on Linux.

chrome/browser/ui/panels/panel_browser_window_gtk.cc

Index: chrome/browser/ui/panels/panel_browser_window_gtk.cc
diff --git a/chrome/browser/ui/panels/panel_browser_window_gtk.cc b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
index c9342e02c86ccdf031a714d97855f9a16d7598d2..857b50be4dad669e98a67a7ed186f033f2dce7f4 100644
--- a/chrome/browser/ui/panels/panel_browser_window_gtk.cc
+++ b/chrome/browser/ui/panels/panel_browser_window_gtk.cc
@@ -70,6 +70,7 @@ PanelBrowserWindowGtk::~PanelBrowserWindowGtk() {
     DestroyDragWidget();
   }
   panel_->OnNativePanelClosed();
+  ui::WorkAreaWatcherX::RemoveObserver(this);
 }
 
 void PanelBrowserWindowGtk::Init() {
@@ -92,6 +93,15 @@ void PanelBrowserWindowGtk::Init() {
                    G_CALLBACK(OnTitlebarButtonPressEventThunk), this);
   g_signal_connect(titlebar_widget(), "button-release-event",
                    G_CALLBACK(OnTitlebarButtonReleaseEventThunk), this);
+
+  // Strictly speaking we should have a single observer for work area changed

[Dmitry Titov, 2011/11/18 04:56:37]

Not sure that long comment has to be here. If it's not a TODO, I don't see what
it adds. Remove?

[prasadt, 2011/11/18 22:31:42]

Just a clarification in case someone wonders why its done this way. Removed it
as it doesn't seem to help.

+  // notification. There are a few reasons for doing it this way:
+  // 1) Keep it consistent with the way we do it on other platforms.
+  // 2) This is a rare enough event to create a separate class with
+  //    implementations for all platforms.
+  // 3) It may not be possible to listen to this event without assoicating it
+  //    with a window on all platforms.
+  ui::WorkAreaWatcherX::AddObserver(this);
 }
 
 bool PanelBrowserWindowGtk::GetWindowEdge(int x, int y, GdkWindowEdge* edge) {
@@ -225,6 +235,10 @@ BrowserWindowGtk::TitleDecoration PanelBrowserWindowGtk::GetWindowTitle(
   }
 }
 
+void PanelBrowserWindowGtk::WorkAreaChanged() {
+  panel_->manager()->OnDisplayChanged();
+}
+
 void PanelBrowserWindowGtk::ShowPanel() {
   Show();
 }