Only execute shortcut handler on active application.

The shortcut handler is already executed when application becomes
active.
Executing it in performActionForShortcutItem will result in two
execution which can cause issues (e.g. if action is to trigger camera).

Bug: 1000940
Change-Id: Id89a1c1c88fc9594599772cb0170c7c6e08deded
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1789523Reviewed-by: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Rohit Rao <rohitrao@chromium.org>
Commit-Queue: Rohit Rao <rohitrao@chromium.org>
Auto-Submit: Olivier Robin <olivierrobin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#695763}

ios/chrome/app/application_delegate/user_activity_handler.mm

@@ -209,7 +209,9 @@ NSString* const kShortcutQRScanner = @"OpenQRScanner";
   BOOL handledShortcutItem =
       [UserActivityHandler handleShortcutItem:shortcutItem
                            startupInformation:startupInformation];
-  if (handledShortcutItem) {
+  BOOL isActive = [[UIApplication sharedApplication] applicationState] ==
+                  UIApplicationStateActive;
+  if (handledShortcutItem && isActive) {
     [UserActivityHandler
         handleStartupParametersWithTabOpener:tabOpener
                           startupInformation:startupInformation