Fix the bug of multiple overlays.

ash/wm/overlay_event_filter_unittest.cc

Index: ash/wm/overlay_event_filter_unittest.cc
diff --git a/ash/wm/overlay_event_filter_unittest.cc b/ash/wm/overlay_event_filter_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..618e4d8d13aacaf44ac7e8efe5937486575747d8
--- /dev/null
+++ b/ash/wm/overlay_event_filter_unittest.cc
@@ -0,0 +1,37 @@
+// Copyright 2014 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.
+
+#include "ash/wm/overlay_event_filter.h"
+
+#include "ash/shell.h"
+#include "ash/test/ash_test_base.h"
+#include "ash/test/test_overlay_delegate.h"
+
+namespace ash {
+namespace test {
+
+typedef AshTestBase OverlayEventFilterTest;
+
+// Tests of the multiple overlay delegates attempt to activate, in that case
+// Cancel() of the existing delegate should be called.
+// See http://crbug.com/341958
+TEST_F(OverlayEventFilterTest, CancelAtActivating) {
+  TestOverlayDelegate d1;
+  TestOverlayDelegate d2;
+
+  Shell::GetInstance()->overlay_filter()->Activate(&d1);
+  EXPECT_EQ(0, d1.GetCancelCountAndReset());
+  EXPECT_EQ(0, d2.GetCancelCountAndReset());
+
+  Shell::GetInstance()->overlay_filter()->Activate(&d2);
+  EXPECT_EQ(1, d1.GetCancelCountAndReset());
+  EXPECT_EQ(0, d2.GetCancelCountAndReset());
+
+  Shell::GetInstance()->overlay_filter()->Cancel();
+  EXPECT_EQ(0, d1.GetCancelCountAndReset());
+  EXPECT_EQ(1, d2.GetCancelCountAndReset());
+}
+
+}  // namespace test
+}  // namespace ash