Draw background of Linux extension toolstrips.

chrome/browser/gtk/extension_shelf_gtk.h

Index: chrome/browser/gtk/extension_shelf_gtk.h
diff --git a/chrome/browser/gtk/extension_shelf_gtk.h b/chrome/browser/gtk/extension_shelf_gtk.h
index 550f9ecc90080c3c5d221e4a589a74315b027c8f..4c124ebedb44d8311ff100763af24a89e345aecd 100644
--- a/chrome/browser/gtk/extension_shelf_gtk.h
+++ b/chrome/browser/gtk/extension_shelf_gtk.h
@@ -57,6 +57,9 @@ class ExtensionShelfGtk : public ExtensionShelfModelObserver,
   // Create the contents of the extension shelf.
   void Init(Profile* profile);
 
+  // Lazily initialize background bitmap. Can be called many times.
+  void InitBackground();
+
   // Determines what is our target height and sets it.
   void AdjustHeight();
 
@@ -80,6 +83,9 @@ class ExtensionShelfGtk : public ExtensionShelfModelObserver,
   // Used to position all children.
   GtkWidget* shelf_hbox_;
 
+  // Lazily-initialized background for toolstrips.
+  scoped_ptr<SkBitmap> background_;
+
   GtkThemeProvider* theme_provider_;
 
   // The model representing the toolstrips on the shelf.