[test fixlet] Add tests for the zoom icon in the location bar on GTK.

chrome/browser/ui/gtk/zoom_bubble_gtk.cc

Index: chrome/browser/ui/gtk/zoom_bubble_gtk.cc
diff --git a/chrome/browser/ui/gtk/zoom_bubble_gtk.cc b/chrome/browser/ui/gtk/zoom_bubble_gtk.cc
index 89bdbf577d56632623070911732e83a91a854dbf..62f4fa790767f1876623019680f33aa1a239a6a8 100644
--- a/chrome/browser/ui/gtk/zoom_bubble_gtk.cc
+++ b/chrome/browser/ui/gtk/zoom_bubble_gtk.cc
@@ -20,9 +20,6 @@
 
 namespace {
 
-// Pointer to singleton object (NULL if no bubble is open).
-ZoomBubbleGtk* g_bubble = NULL;
-
 // Number of milliseconds the bubble should stay open for if it will auto-close.
 const int kBubbleCloseDelay = 1500;
 
@@ -34,6 +31,9 @@ const int kBubbleAnchorHeight = 25;
 }  // namespace
 
 // static
+ZoomBubbleGtk* ZoomBubbleGtk::g_bubble = NULL;
+
+// static
 void ZoomBubbleGtk::Show(GtkWidget* anchor,
                          TabContents* tab_contents,
                          bool auto_close) {
@@ -61,6 +61,11 @@ void ZoomBubbleGtk::Close() {
     g_bubble->CloseBubble();
 }
 
+// static
+bool ZoomBubbleGtk::IsShowing() {
+  return g_bubble != NULL;
+}
+
 ZoomBubbleGtk::ZoomBubbleGtk(GtkWidget* anchor,
                              TabContents* tab_contents,
                              bool auto_close)