Close ExtensionPopup on tab switches; add test.

chrome/browser/ui/views/extensions/extension_popup.h

Index: chrome/browser/ui/views/extensions/extension_popup.h
diff --git a/chrome/browser/ui/views/extensions/extension_popup.h b/chrome/browser/ui/views/extensions/extension_popup.h
index 437806a85c8ed6ecb2c76fcdb9de21f67c5b7edf..aa4be8f5b4d8b5856af93f5918bf5eb551c4a6ad 100644
--- a/chrome/browser/ui/views/extensions/extension_popup.h
+++ b/chrome/browser/ui/views/extensions/extension_popup.h
@@ -7,6 +7,7 @@
 
 #include "base/callback.h"
 #include "base/compiler_specific.h"
+#include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/views/extensions/extension_view_views.h"
 #include "content/public/browser/notification_observer.h"
 #include "content/public/browser/notification_registrar.h"
@@ -36,7 +37,8 @@ class ExtensionPopup : public views::BubbleDelegateView,
                        public aura::client::ActivationChangeObserver,
 #endif
                        public ExtensionViewViews::Container,
-                       public content::NotificationObserver {
+                       public content::NotificationObserver,
+                       public TabStripModelObserver {
  public:
   enum ShowAction {
     SHOW,
@@ -84,6 +86,12 @@ class ExtensionPopup : public views::BubbleDelegateView,
                                  aura::Window* lost_active) OVERRIDE;
 #endif
 
+  // TabStripModelObserver overrides.
+  virtual void ActiveTabChanged(content::WebContents* old_contents,
+                                content::WebContents* new_contents,
+                                int index,
+                                int reason) OVERRIDE;
+
   // The min/max height of popups.
   static const int kMinWidth;
   static const int kMinHeight;