Move aligned memory utilities to rtc_base/memory/

This moves them from an API directory (system_wrappers/include/) to a
non-API directory, which is exactly what we want for utilities like
this.

BUG=webrtc:8445

Change-Id: I6dc34fe662f5d87b3b5288d33055345bc6bf91db
Reviewed-on: https://webrtc-review.googlesource.com/21164
Commit-Queue: Karl Wiberg <kwiberg@webrtc.org>
Reviewed-by: Danil Chapovalov <danilchap@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#22567}

rtc_base/memory/aligned_array_unittest.cc

@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "rtc_base/memory/aligned_array.h"
+
+#include <stdint.h>
+
+#include "test/gtest.h"
+
+namespace {
+
+bool IsAligned(const void* ptr, size_t alignment) {
+  return reinterpret_cast<uintptr_t>(ptr) % alignment == 0;
+}
+
+}  // namespace
+
+namespace webrtc {
+
+TEST(AlignedArrayTest, CheckAlignment) {
+  AlignedArray<bool> arr(10, 7, 128);
+  ASSERT_TRUE(IsAligned(arr.Array(), 128));
+  for (size_t i = 0; i < 10; ++i) {
+    ASSERT_TRUE(IsAligned(arr.Row(i), 128));
+    ASSERT_EQ(arr.Row(i), arr.Array()[i]);
+  }
+}
+
+TEST(AlignedArrayTest, CheckOverlap) {
+  AlignedArray<size_t> arr(10, 7, 128);
+
+  for (size_t i = 0; i < 10; ++i) {
+    for (size_t j = 0; j < 7; ++j) {
+      arr.At(i, j) = 20 * i + j;
+    }
+  }
+
+  for (size_t i = 0; i < 10; ++i) {
+    for (size_t j = 0; j < 7; ++j) {
+      ASSERT_EQ(arr.At(i, j), 20 * i + j);
+      ASSERT_EQ(arr.Row(i)[j], 20 * i + j);
+      ASSERT_EQ(arr.Array()[i][j], 20 * i + j);
+    }
+  }
+}
+
+TEST(AlignedArrayTest, CheckRowsCols) {
+  AlignedArray<bool> arr(10, 7, 128);
+  ASSERT_EQ(arr.rows(), 10u);
+  ASSERT_EQ(arr.cols(), 7u);
+}
+
+}  // namespace webrtc