Add MemoryWedge to ios/.

ios/chrome/browser/memory/memory_wedge_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 "ios/chrome/browser/memory/memory_wedge.h"
+
+#include "base/macros.h"
+#include "ios/chrome/browser/memory/memory_metrics.h"
+#include "testing/gtest/include/gtest/gtest-param-test.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace memory_wedge {
+
+namespace {
+
+// The number of bytes in a megabyte.
+const uint64 kNumBytesInMB = 1024 * 1024;
+
+// Note: in the following tests, only memory_util::GetInternalVMBytes,
+// and memory_util::GetRealMemoryUsedInBytes are used to check the state of the
+// memory before and after an action.
+// memory_util::GetFreePhysicalBytes and memory_util::GetDirtyVMBytes are not
+// used because external events can change these values, making them not
+// reliable.
+
+// Performs a snapshot of the memory when constructed. Deviation from the
+// initial values can be verified with VerifyDeviation. The comparison is
+// on the integer part of the values in MB.
+class MemoryChecker {
+ public:
+  MemoryChecker() {
+    internal_vm_ = memory_util::GetInternalVMBytes() / kNumBytesInMB;
+    real_memory_used_ = memory_util::GetRealMemoryUsedInBytes() / kNumBytesInMB;
+  }
+
+  // Verifies that the memory metrics deviated only by |deviation| in MB.
+  void VerifyDeviation(uint64 deviation) const {
+    EXPECT_NEAR(memory_util::GetInternalVMBytes() / kNumBytesInMB,
+                deviation + internal_vm_, 1);
+    EXPECT_NEAR(memory_util::GetRealMemoryUsedInBytes() / kNumBytesInMB,
+                deviation + real_memory_used_, 1);
+  }
+
+ private:
+  uint64 internal_vm_;
+  uint64 real_memory_used_;
+
+  DISALLOW_COPY_AND_ASSIGN(MemoryChecker);
+};
+
+class MemoryWedgeTest : public testing::TestWithParam<size_t> {};
+
+}  // namespace
+
+// Checks that the wedge size passed to AddWedge is indeed added to the global
+// footprint of the app.
+TEST_P(MemoryWedgeTest, WedgeSize) {
+  const MemoryChecker memory_checker;
+  size_t wedge_size = GetParam();
+
+  AddWedge(wedge_size);
+
+  memory_checker.VerifyDeviation(wedge_size);
+  if (wedge_size > 0)
+    RemoveWedgeForTesting();
+}
+
+INSTANTIATE_TEST_CASE_P(
+    /* No InstantiationName */,
+    MemoryWedgeTest,
+    testing::Values(0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100));
+
+}  // namespace memory_wedge