Don't hide the reparenting tab while detaching

chrome/android/javatests/src/org/chromium/chrome/browser/customtabs/CustomTabActivityTest.java

 // Copyright 2015 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.customtabs;
 
 import static org.chromium.base.test.util.Restriction.RESTRICTION_TYPE_NON_LOW_END_DEVICE;
 
 import android.app.Activity;
 import android.app.Application;
@@ skipping 1211 matching lines @@
             fail();
         }
         return connection;
     }
 
     private ChromeActivity reparentAndVerifyTab() throws InterruptedException {
         ActivityResult result = null;
         final ActivityMonitor monitor = getInstrumentation().addMonitor(
                 ChromeTabbedActivity.class.getName(), result, false);
         final Tab tabToBeReparented = mActivity.getActivityTab();
+        final CallbackHelper tabHiddenHelper = new CallbackHelper();
+        tabToBeReparented.addObserver(new EmptyTabObserver() {

[gone, 2016/04/26 22:05:38]

This Observer should probably be removed at some point.

[Yusuf, 2016/04/26 22:10:15]

Done.

+            @Override
+            public void onHidden(Tab tab) {
+                tabHiddenHelper.notifyCalled();
+            }
+        });
         ThreadUtils.postOnUiThread(new Runnable() {
             @Override
             public void run() {
                 mActivity.openCurrentUrlInBrowser(true);
                 assertNull(mActivity.getActivityTab());
             }
         });
         CriteriaHelper.pollInstrumentationThread(new Criteria() {
             @Override
             public boolean isSatisfied() {
@@ skipping 12 matching lines @@
         CriteriaHelper.pollUiThread((new Criteria() {
             @Override
             public boolean isSatisfied() {
                 return mActivity.isActivityDestroyed();
             }
         }));
         assertEquals(newActivity.getWindowAndroid(), tabToBeReparented.getWindowAndroid());
         assertEquals(newActivity.getWindowAndroid(),
                 tabToBeReparented.getContentViewCore().getWindowAndroid());
         assertFalse(tabToBeReparented.getDelegateFactory() instanceof CustomTabDelegateFactory);
+        assertEquals("The tab should never be hidden during the reparenting process",
+                0, tabHiddenHelper.getCallCount());
         return newActivity;
     }
 
     private IBinder warmUpAndLaunchUrlWithSession(ICustomTabsCallback cb)
             throws InterruptedException {
         CustomTabsConnection connection = warmUpAndWait();
         connection.newSession(cb);
         Context context = getInstrumentation().getTargetContext().getApplicationContext();
         startCustomTabActivityWithIntent(CustomTabsTestUtils.createMinimalCustomTabIntent(
                 context, mTestPage, cb.asBinder()));
@@ skipping 74 matching lines @@
                 if (jsonText.equalsIgnoreCase("null")) jsonText = "";
                 value = jsonText;
             } catch (InterruptedException | TimeoutException e) {
                 e.printStackTrace();
                 return false;
             }
             return TextUtils.equals(mExpected, value);
         }
     }
 }