ui: Fix removing a number from the SequentialIDGenerator.

ui/base/sequential_id_generator_unittest.cc

 // Copyright (c) 2013 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 "ui/base/sequential_id_generator.h"
 
 #include "base/logging.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace ui {
@@ skipping 20 matching lines @@
   EXPECT_TRUE(generator.HasGeneratedIDFor(1));
 
   generator.ReleaseGeneratedID(3);
   EXPECT_EQ(3U, generator.GetGeneratedID(45));
   EXPECT_TRUE(generator.HasGeneratedIDFor(45));
 
   generator.ReleaseNumber(45);
   EXPECT_FALSE(generator.HasGeneratedIDFor(45));
 }
 
+TEST(SequentialIDGeneratorTest, RemoveMultipleNumbers) {
+  const uint32 kMinID = 4;
+  SequentialIDGenerator generator(kMinID);
+
+  EXPECT_EQ(4U, generator.GetGeneratedID(45));
+  EXPECT_EQ(5U, generator.GetGeneratedID(55));
+  EXPECT_EQ(6U, generator.GetGeneratedID(15));
+
+  generator.ReleaseNumber(45);
+  EXPECT_FALSE(generator.HasGeneratedIDFor(45));
+  generator.ReleaseNumber(15);
+  EXPECT_FALSE(generator.HasGeneratedIDFor(15));
+
+  EXPECT_EQ(5U, generator.GetGeneratedID(55));
+  EXPECT_EQ(4U, generator.GetGeneratedID(12));
+
+  generator.ReleaseNumber(12);
+  generator.ReleaseNumber(55);
+  EXPECT_EQ(4U, generator.GetGeneratedID(0));
+}
+
 }  // namespace ui