Ensure only one live search engine promo.

chrome/android/java/src/org/chromium/chrome/browser/locale/DefaultSearchEnginePromoDialog.java

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.chrome.browser.locale;
 
+import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.DialogInterface;
 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.widget.Button;
 
 import org.chromium.base.Callback;
 import org.chromium.base.VisibleForTesting;
 import org.chromium.base.metrics.RecordUserAction;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.locale.LocaleManager.SearchEnginePromoType;
 import org.chromium.chrome.browser.widget.PromoDialog;
 import org.chromium.chrome.browser.widget.RadioButtonLayout;
 
 /** A dialog that forces the user to choose a default search engine. */
 public class DefaultSearchEnginePromoDialog extends PromoDialog {
     /** Notified about events happening to the dialog. */
     public static interface DefaultSearchEnginePromoDialogObserver {
         void onDialogShown(DefaultSearchEnginePromoDialog shownDialog);
     }
     private static DefaultSearchEnginePromoDialogObserver sObserver;
 
+    @SuppressLint("StaticFieldLeak")
+    private static DefaultSearchEnginePromoDialog sCurrentDialog;
+
     /** Used to determine the promo dialog contents. */
     @SearchEnginePromoType
     private final int mDialogType;
 
     /** Called when the dialog is dismissed after the user has chosen a search engine. */
     private final Callback<Boolean> mOnDismissed;
 
     /** Encapsulates most of the logic for filling the dialog and handling clicks. */
     private DefaultSearchEngineDialogHelper mHelper;
 
@@ skipping 44 matching lines @@
                 dismiss();
             }
         };
         mHelper = new DefaultSearchEngineDialogHelper(
                 mDialogType, radioButtons, okButton, dismissRunnable);
     }
 
     @Override
     public void show() {
         super.show();
+        if (sCurrentDialog != null) sCurrentDialog.dismiss();
+        setCurrentDialog(this);
+
         if (mDialogType == LocaleManager.SEARCH_ENGINE_PROMO_SHOW_NEW) {
             RecordUserAction.record("SearchEnginePromo.NewDevice.Shown.Dialog");
         } else if (mDialogType == LocaleManager.SEARCH_ENGINE_PROMO_SHOW_EXISTING) {
             RecordUserAction.record("SearchEnginePromo.ExistingDevice.Shown.Dialog");
         }
         if (sObserver != null) sObserver.onDialogShown(this);
     }
 
     @Override
     public void onDismiss(DialogInterface dialog) {
         if (mHelper.getCurrentlySelectedKeyword() == null) {
             // If no selection, finish the Activity so that the user has to respond to the dialog
             // next time.
             if (getOwnerActivity() != null) getOwnerActivity().finish();
         }
 
         if (mOnDismissed != null) {
             mOnDismissed.onResult(mHelper.getCurrentlySelectedKeyword() != null);
         }
+
+        if (sCurrentDialog == this) setCurrentDialog(null);
     }
 
     /** See {@link #sObserver}. */
     @VisibleForTesting
     @Nullable
     public static void setObserverForTests(DefaultSearchEnginePromoDialogObserver observer) {
         sObserver = observer;
     }
+
+    /** @return The current visible Default Search Engine dialog. */
+    static DefaultSearchEnginePromoDialog getCurrentDialog() {
+        return sCurrentDialog;
+    }
+
+    private static void setCurrentDialog(DefaultSearchEnginePromoDialog dialog) {
+        sCurrentDialog = dialog;
+    }
 }