Do not show permission bubble when browser is not active

chrome/browser/permissions/permission_request_manager.h

Index: chrome/browser/permissions/permission_request_manager.h
diff --git a/chrome/browser/permissions/permission_request_manager.h b/chrome/browser/permissions/permission_request_manager.h
index b2df0b9d08a0a07172227246d1df40568b7ba35b..0ce83b550fe9f21bc79acdbfaf1bae011f2a62db 100644
--- a/chrome/browser/permissions/permission_request_manager.h
+++ b/chrome/browser/permissions/permission_request_manager.h
@@ -11,6 +11,7 @@
 #include "base/gtest_prod_util.h"
 #include "base/memory/weak_ptr.h"
 #include "base/observer_list.h"
+#include "chrome/browser/ui/browser_list_observer.h"
 #include "chrome/browser/ui/permission_bubble/permission_prompt.h"
 #include "content/public/browser/web_contents_observer.h"
 #include "content/public/browser/web_contents_user_data.h"
@@ -39,7 +40,8 @@ class PermissionRequestManagerTestApi;
 class PermissionRequestManager
     : public content::WebContentsObserver,
       public content::WebContentsUserData<PermissionRequestManager>,
-      public PermissionPrompt::Delegate {
+      public PermissionPrompt::Delegate,
+      public chrome::BrowserListObserver {
  public:
   class Observer {
    public:
@@ -142,6 +144,9 @@ class PermissionRequestManager
   void Deny() override;
   void Closing() override;
 
+  // chrome::BrowserListObserver:
+  void OnBrowserSetLastActive(Browser* browser) override;
+
   // Posts a task which will allow the bubble to become visible if it is needed.
   void ScheduleShowBubble();