Upstream Chrome on iOS source code [4/11].

ios/chrome/browser/ui/elements/activity_overlay_coordinator_unittest.mm

+// Copyright 2016 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.
+
+#import "ios/chrome/browser/ui/elements/activity_overlay_coordinator.h"
+
+#include "base/ios/weak_nsobject.h"
+#include "base/test/ios/wait_util.h"
+#import "ios/chrome/browser/ui/elements/activity_overlay_view_controller.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#import "testing/gtest_mac.h"
+
+// Tests that invoking start and stop on the coordinator presents and dismisses
+// the activity overlay view, respectively.
+TEST(ActivityOverlayCoordinatorTest, StartAndStop) {
+  base::WeakNSObject<UIView> overlay_view;
+  @autoreleasepool {
+    UIViewController* base_view_controller =
+        [[[UIViewController alloc] init] autorelease];
+    ActivityOverlayCoordinator* coordinator =
+        [[[ActivityOverlayCoordinator alloc]
+            initWithBaseViewController:base_view_controller] autorelease];
+
+    EXPECT_EQ(0u, [base_view_controller.childViewControllers count]);
+
+    [coordinator start];
+    EXPECT_EQ(1u, [base_view_controller.childViewControllers count]);
+    overlay_view.reset(
+        [base_view_controller.childViewControllers firstObject].view);
+    EXPECT_TRUE(
+        [[base_view_controller.view subviews] containsObject:overlay_view]);
+
+    [coordinator stop];
+    EXPECT_EQ(0u, [base_view_controller.childViewControllers count]);
+  }
+  EXPECT_FALSE(overlay_view.get());
+}