Close the save card bubble on tab switch.

chrome/browser/ui/views/autofill/save_card_icon_view.h

Index: chrome/browser/ui/views/autofill/save_card_icon_view.h
diff --git a/chrome/browser/ui/views/autofill/save_card_icon_view.h b/chrome/browser/ui/views/autofill/save_card_icon_view.h
index f591420faba5724cef50a760d4fb31e6b10aec4a..aeed972fb2b9164e4b2c1a109062df1ea3b490f9 100644
--- a/chrome/browser/ui/views/autofill/save_card_icon_view.h
+++ b/chrome/browser/ui/views/autofill/save_card_icon_view.h
@@ -6,6 +6,7 @@
 #define CHROME_BROWSER_UI_VIEWS_AUTOFILL_SAVE_CARD_ICON_VIEW_H_
 
 #include "base/macros.h"
+#include "chrome/browser/ui/tabs/tab_strip_model_observer.h"
 #include "chrome/browser/ui/views/location_bar/bubble_icon_view.h"
 
 class Browser;
@@ -13,10 +14,12 @@ class CommandUpdater;
 
 namespace autofill {
 
+class SaveCardBubbleControllerImpl;
+
 // The location bar icon to show the Save Credit Card bubble where the user can
 // choose to save the credit card info to use again later without re-entering
 // it.
-class SaveCardIconView : public BubbleIconView {
+class SaveCardIconView : public BubbleIconView, public TabStripModelObserver {
  public:
   explicit SaveCardIconView(CommandUpdater* command_updater, Browser* browser);
   ~SaveCardIconView() override;
@@ -27,7 +30,12 @@ class SaveCardIconView : public BubbleIconView {
   views::BubbleDelegateView* GetBubble() const override;
   gfx::VectorIconId GetVectorIcon() const override;
 
+  // TabStripModelObserver:
+  void TabDeactivated(content::WebContents* contents) override;
+
  private:
+  SaveCardBubbleControllerImpl* GetController() const;
+
   // May be nullptr.
   Browser* browser_;