Added MemoryMonitor for Linux (with test)

components/memory_coordinator/browser/memory_monitor_linux_unittest.cc

Index: components/memory_coordinator/browser/memory_monitor_linux_unittest.cc
diff --git a/components/memory_coordinator/browser/memory_monitor_linux_unittest.cc b/components/memory_coordinator/browser/memory_monitor_linux_unittest.cc
new file mode 100644
index 0000000000000000000000000000000000000000..df2ceeb7e88964168f9c675ab1b1577895153f07
--- /dev/null
+++ b/components/memory_coordinator/browser/memory_monitor_linux_unittest.cc
@@ -0,0 +1,77 @@
+// Copyright (c) 2016 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 "components/memory_coordinator/browser/memory_monitor_linux.h"
+
+#include "components/memory_coordinator/browser/test_memory_monitor.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace memory_coordinator {
+
+namespace {
+
+// A delegate that allows mocking the various inputs to MemoryMonitorLinux.
+class TestMemoryMonitorLinuxDelegate : public TestMemoryMonitorDelegate {
+ public:
+  TestMemoryMonitorLinuxDelegate() {}
+
+  void SetAvailableMemoryKB(int available_memory_kb) {
+    // If this is set, other "free" values are ignored.
+    mem_info_.available = available_memory_kb;
+  }
+
+  void SetFreeMemoryKB(int free_kb, int cached_kb, int buffers_kb) {
+    mem_info_.free = free_kb;
+    mem_info_.cached = cached_kb;
+    mem_info_.buffers = buffers_kb;
+
+    // Only if this is zero will the above values be used.
+    mem_info_.available = 0;
+  }
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(TestMemoryMonitorLinuxDelegate);
+};
+
+class TestMemoryMonitorLinux : public MemoryMonitorLinux {};
+
+static const int kKBperMB = 1024;
+
+}  // namespace
+
+class MemoryMonitorLinuxTest : public testing::Test {
+ public:
+  TestMemoryMonitorLinuxDelegate delegate_;
+  std::unique_ptr<MemoryMonitorLinux> monitor_;
+};
+
+TEST_F(MemoryMonitorLinuxTest, Create) {
+  delegate_.SetTotalMemoryKB(100000 * kKBperMB);
+  monitor_ = MemoryMonitorLinux::Create(&delegate_);
+  EXPECT_EQ(0U, delegate_.calls());
+}
+
+TEST_F(MemoryMonitorLinuxTest, GetFreeMemoryUntilCriticalMB) {
+  delegate_.SetTotalMemoryKB(1000 * kKBperMB);
+
+  monitor_.reset(new MemoryMonitorLinux(&delegate_));
+  EXPECT_EQ(0u, delegate_.calls());
+
+  delegate_.SetAvailableMemoryKB(200 * kKBperMB);
+  EXPECT_EQ(200, monitor_->GetFreeMemoryUntilCriticalMB());
+  EXPECT_EQ(1U, delegate_.calls());
+  delegate_.ResetCalls();
+
+  delegate_.SetFreeMemoryKB(64 * kKBperMB, 32 * kKBperMB, 16 * kKBperMB);
+  EXPECT_EQ(112, monitor_->GetFreeMemoryUntilCriticalMB());
+  EXPECT_EQ(1U, delegate_.calls());
+  delegate_.ResetCalls();
+
+  delegate_.SetFreeMemoryKB(0, 0, 0);
+  EXPECT_EQ(0, monitor_->GetFreeMemoryUntilCriticalMB());
+  EXPECT_EQ(1U, delegate_.calls());
+  delegate_.ResetCalls();
+}
+
+}  // namespace memory_coordinator