Correct alignment in ContiguousContainer::appendByMoving()

cc/base/contiguous_container_unittest.cc

 // 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.
 
 #include <stddef.h>
 
 #include "cc/base/contiguous_container.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
@@ skipping 493 matching lines @@
   // Clearing should restore the capacity of the container to the same as a
   // newly allocated one (without reserved capacity requested).
   ContiguousContainer<Point2D, kPointAlignment> list(kMaxPointSize);
   size_t empty_capacity = list.GetCapacityInBytes();
   list.AllocateAndConstruct<Point2D>();
   list.AllocateAndConstruct<Point2D>();
   list.Clear();
   EXPECT_EQ(empty_capacity, list.GetCapacityInBytes());
 }
 
+TEST(ContiguousContainerTest, Alignment) {
+  const size_t max_align = ALIGNOF(long double);
+  ContiguousContainer<Point2D, max_align> list(kMaxPointSize);
+
+  list.AllocateAndConstruct<Point2D>();
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AllocateAndConstruct<Point2D>();
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AllocateAndConstruct<Point3D>();
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AllocateAndConstruct<Point3D>();
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AllocateAndConstruct<Point2D>();
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+
+  list.AppendByMoving(&list[0], sizeof(Point2D));
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AppendByMoving(&list[1], sizeof(Point2D));
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AppendByMoving(&list[2], sizeof(Point3D));
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AppendByMoving(&list[3], sizeof(Point3D));
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+  list.AppendByMoving(&list[4], sizeof(Point2D));
+  EXPECT_EQ(0u, reinterpret_cast<intptr_t>(&list.last()) & (max_align - 1));
+}
+
 }  // namespace
 }  // namespace cc