Using the new MemoryPressureListener instead of the LowMemoryObserver when the enhanced memory mana…

base/chromeos/memory_pressure_observer_chromeos_unittest.cc

+// Copyright 2014 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 "base/basictypes.h"
+#include "base/chromeos/memory_pressure_observer_chromeos.h"
+#include "base/memory/memory_pressure_listener.h"
+#include "base/message_loop/message_loop.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace base {
+
+namespace {
+
+// True if the memory notifier got called.
+// Do not read/modify value directly.
+bool on_memory_pressure_called = false;
+
+// If the memory notifier got called, this is the memory pressure reported.
+MemoryPressureListener::MemoryPressureLevel on_memory_pressure_level =
+    MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE;
+
+// Processes OnMemoryPressure calls.
+void OnMemoryPressure(MemoryPressureListener::MemoryPressureLevel level) {
+  on_memory_pressure_called = true;
+  on_memory_pressure_level = level;
+}
+
+// Resets the indicator for memory pressure.
+void ResetOnMemoryPressureCalled() {
+  on_memory_pressure_called = false;
+}
+
+// Returns true when OnMemoryPressure was called (and resets it).
+bool WasOnMemoryPressureCalled() {
+  bool b = on_memory_pressure_called;
+  ResetOnMemoryPressureCalled();
+  return b;
+}
+
+}  // namespace
+
+class TestMemoryPressureObserver : public MemoryPressureObserverChromeOS {
+ public:
+  TestMemoryPressureObserver() : memory_in_percent_override_(0) {
+    // Disable any timers which are going on and set a special memory reporting
+    // function.
+    StopObserving();
+  }
+  ~TestMemoryPressureObserver() override {}
+
+  void SetMemoryInPercentOverride(int percent) {
+    memory_in_percent_override_ = percent;
+  }
+
+  void CheckMemoryPressureForTest() {
+    CheckMemoryPressure();
+  }
+
+ private:
+  int GetUsedMemoryInPercent() override {
+    return memory_in_percent_override_;
+  }
+
+  int memory_in_percent_override_;
+  DISALLOW_COPY_AND_ASSIGN(TestMemoryPressureObserver);
+};
+
+// This test tests the various transition states from memory pressure, looking
+// for the correct behavior on event reposting as well as state updates.
+TEST(MemoryPressureObserverChromeOSTest, CheckMemoryPressure) {
+  base::MessageLoopForUI message_loop;
+  scoped_ptr<TestMemoryPressureObserver> observer(
+      new TestMemoryPressureObserver);
+  scoped_ptr<MemoryPressureListener> listener(
+      new MemoryPressureListener(base::Bind(&OnMemoryPressure)));
+  // Checking the memory pressure while 0% are used should not produce any
+  // events.
+  observer->SetMemoryInPercentOverride(0);
+  ResetOnMemoryPressureCalled();
+
+  observer->CheckMemoryPressureForTest();
+  message_loop.RunUntilIdle();
+  EXPECT_FALSE(WasOnMemoryPressureCalled());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_NONE,
+            observer->GetCurrentPressureLevel());
+
+  // Setting the memory level to 80% should produce a moderate pressure level.
+  observer->SetMemoryInPercentOverride(80);
+  observer->CheckMemoryPressureForTest();
+  message_loop.RunUntilIdle();
+  EXPECT_TRUE(WasOnMemoryPressureCalled());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+            observer->GetCurrentPressureLevel());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+            on_memory_pressure_level);
+
+  // We need to check that the event gets reposted after a while.
+  int i = 0;
+  for (; i < 100; i++) {
+    observer->CheckMemoryPressureForTest();
+    message_loop.RunUntilIdle();
+    EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+              observer->GetCurrentPressureLevel());
+    if (WasOnMemoryPressureCalled()) {
+      EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+                on_memory_pressure_level);
+      break;
+    }
+  }
+  // Should be more then 5 and less then 100.
+  EXPECT_LE(5, i);
+  EXPECT_GE(99, i);
+
+  // Setting the memory usage to 99% should produce critical levels.
+  observer->SetMemoryInPercentOverride(99);
+  observer->CheckMemoryPressureForTest();
+  message_loop.RunUntilIdle();
+  EXPECT_TRUE(WasOnMemoryPressureCalled());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            on_memory_pressure_level);
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            observer->GetCurrentPressureLevel());
+
+  // Calling it again should immediately produce a second call.
+  observer->CheckMemoryPressureForTest();
+  message_loop.RunUntilIdle();
+  EXPECT_TRUE(WasOnMemoryPressureCalled());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            on_memory_pressure_level);
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_CRITICAL,
+            observer->GetCurrentPressureLevel());
+
+  // When lowering the pressure again we should not get an event, but the
+  // pressure should go back to moderate.
+  observer->SetMemoryInPercentOverride(80);
+  observer->CheckMemoryPressureForTest();
+  message_loop.RunUntilIdle();
+  EXPECT_FALSE(WasOnMemoryPressureCalled());
+  EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+            observer->GetCurrentPressureLevel());
+
+  // We should need exactly the same amount of calls as before, before the next
+  // call comes in.
+  int j = 0;
+  for (; j < 100; j++) {
+    observer->CheckMemoryPressureForTest();
+    message_loop.RunUntilIdle();
+    EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+              observer->GetCurrentPressureLevel());
+    if (WasOnMemoryPressureCalled()) {
+      EXPECT_EQ(MemoryPressureListener::MEMORY_PRESSURE_LEVEL_MODERATE,
+                on_memory_pressure_level);
+      break;
+    }
+  }
+  // We should have needed exactly the same amount of checks as before.
+  EXPECT_EQ(j, i);
+}
+
+}  // namespace base