Revert of base: Introduce an explicit call for reducing emulated discardable memory usage.

base/memory/discardable_memory_manager_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/memory/discardable_memory_manager.h"
 
 #include "base/bind.h"
+#include "base/run_loop.h"
 #include "base/synchronization/waitable_event.h"
 #include "base/threading/thread.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace base {
 namespace {
 
 class TestAllocationImpl : public internal::DiscardableMemoryManagerAllocation {
  public:
   TestAllocationImpl() : is_allocated_(false), is_locked_(false) {}
@@ skipping 20 matching lines @@
 
  private:
   bool is_allocated_;
   bool is_locked_;
 };
 
 // Tests can assume that the default limit is at least 1024. Tests that rely on
 // something else needs to explicit set the limit.
 const size_t kDefaultMemoryLimit = 1024;
 const size_t kDefaultSoftMemoryLimit = kDefaultMemoryLimit;
+const size_t kDefaultBytesToKeepUnderModeratePressure = kDefaultMemoryLimit;
 
 class TestDiscardableMemoryManagerImpl
     : public internal::DiscardableMemoryManager {
  public:
   TestDiscardableMemoryManagerImpl()
       : DiscardableMemoryManager(kDefaultMemoryLimit,
                                  kDefaultSoftMemoryLimit,
+                                 kDefaultBytesToKeepUnderModeratePressure,
                                  TimeDelta::Max()) {}
 
   void SetNow(TimeTicks now) { now_ = now; }
 
  private:
   // Overriden from internal::DiscardableMemoryManager:
   virtual TimeTicks Now() const OVERRIDE { return now_; }
 
   TimeTicks now_;
 };
 
 class DiscardableMemoryManagerTestBase {
  public:
-  DiscardableMemoryManagerTestBase() {}
+  DiscardableMemoryManagerTestBase() {
+    manager_.RegisterMemoryPressureListener();
+  }
 
  protected:
   enum LockStatus {
     LOCK_STATUS_FAILED,
     LOCK_STATUS_PURGED,
     LOCK_STATUS_SUCCESS
   };
 
   size_t BytesAllocated() const { return manager_.GetBytesAllocatedForTest(); }
 
   void SetMemoryLimit(size_t bytes) { manager_.SetMemoryLimit(bytes); }
 
   void SetSoftMemoryLimit(size_t bytes) { manager_.SetSoftMemoryLimit(bytes); }
 
+  void SetBytesToKeepUnderModeratePressure(size_t bytes) {
+    manager_.SetBytesToKeepUnderModeratePressure(bytes);
+  }
+
   void SetHardMemoryLimitExpirationTime(TimeDelta time) {
     manager_.SetHardMemoryLimitExpirationTime(time);
   }
 
   void Register(TestAllocationImpl* allocation, size_t bytes) {
     manager_.Register(allocation, bytes);
   }
 
   void Unregister(TestAllocationImpl* allocation) {
     manager_.Unregister(allocation);
@@ skipping 18 matching lines @@
     manager_.Register(allocation, bytes);
     return Lock(allocation);
   }
 
   bool CanBePurged(TestAllocationImpl* allocation) const {
     return manager_.CanBePurgedForTest(allocation);
   }
 
   void SetNow(TimeTicks now) { manager_.SetNow(now); }
 
-  void PurgeAll() { return manager_.PurgeAll(); }
-
   bool ReduceMemoryUsage() { return manager_.ReduceMemoryUsage(); }
 
-  void ReduceMemoryUsageUntilWithinLimit(size_t bytes) {
-    manager_.ReduceMemoryUsageUntilWithinLimit(bytes);
-  }
-
  private:
+  MessageLoopForIO message_loop_;
   TestDiscardableMemoryManagerImpl manager_;
 };
 
 class DiscardableMemoryManagerTest : public DiscardableMemoryManagerTestBase,
                                      public testing::Test {
  public:
   DiscardableMemoryManagerTest() {}
 };
 
 TEST_F(DiscardableMemoryManagerTest, CreateAndLock) {
@@ skipping 41 matching lines @@
   TestAllocationImpl allocation;
   RegisterAndLock(&allocation, size);
   EXPECT_EQ(1024u, BytesAllocated());
   EXPECT_FALSE(CanBePurged(&allocation));
 
   // Now unlock so we can lock later.
   Unlock(&allocation);
   EXPECT_TRUE(CanBePurged(&allocation));
 
   // Force the system to purge.
-  PurgeAll();
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+
+  // Required because ObserverListThreadSafe notifies via PostTask.
+  RunLoop().RunUntilIdle();
 
   EXPECT_EQ(LOCK_STATUS_PURGED, Lock(&allocation));
   EXPECT_FALSE(CanBePurged(&allocation));
 
   Unlock(&allocation);
   Unregister(&allocation);
 }
 
 TEST_F(DiscardableMemoryManagerTest, LockAfterPurgeAndCannotReallocate) {
   size_t size = 1024;
@@ skipping 84 matching lines @@
       if (allocation_[i].is_locked())
         Unlock(&allocation_[i]);
       Unregister(&allocation_[i]);
     }
   }
 
  private:
   TestAllocationImpl allocation_[3];
 };
 
-// Verify that memory was discarded in the correct order after reducing usage to
-// limit.
-TEST_P(DiscardableMemoryManagerPermutationTest, LRUDiscarded) {
+// Verify that memory was discarded in the correct order after applying
+// memory pressure.
+TEST_P(DiscardableMemoryManagerPermutationTest, LRUDiscardedModeratePressure) {
   RegisterAndUseAllocations();
 
+  SetBytesToKeepUnderModeratePressure(1024);
   SetMemoryLimit(2048);
 
-  ReduceMemoryUsageUntilWithinLimit(1024);
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_MODERATE);
+  RunLoop().RunUntilIdle();
 
   EXPECT_NE(LOCK_STATUS_FAILED, Lock(allocation(2)));
   EXPECT_EQ(LOCK_STATUS_PURGED, Lock(allocation(1)));
   // 0 should still be locked.
   EXPECT_TRUE(allocation(0)->is_locked());
 
   UnlockAndUnregisterAllocations();
 }
 
 // Verify that memory was discarded in the correct order after changing
 // memory limit.
 TEST_P(DiscardableMemoryManagerPermutationTest, LRUDiscardedExceedLimit) {
   RegisterAndUseAllocations();
 
+  SetBytesToKeepUnderModeratePressure(1024);
   SetMemoryLimit(2048);
 
   EXPECT_NE(LOCK_STATUS_FAILED, Lock(allocation(2)));
   EXPECT_EQ(LOCK_STATUS_PURGED, Lock(allocation(1)));
   // 0 should still be locked.
   EXPECT_TRUE(allocation(0)->is_locked());
 
   UnlockAndUnregisterAllocations();
 }
 
 // Verify that no more memory than necessary was discarded after changing
 // memory limit.
 TEST_P(DiscardableMemoryManagerPermutationTest, LRUDiscardedAmount) {
+  SetBytesToKeepUnderModeratePressure(2048);
   SetMemoryLimit(4096);
 
   RegisterAndUseAllocations();
 
   SetMemoryLimit(2048);
 
   EXPECT_EQ(LOCK_STATUS_SUCCESS, Lock(allocation(2)));
   EXPECT_EQ(LOCK_STATUS_PURGED, Lock(allocation(1)));
   // 0 should still be locked.
   EXPECT_TRUE(allocation(0)->is_locked());
 
   UnlockAndUnregisterAllocations();
 }
 
 TEST_P(DiscardableMemoryManagerPermutationTest, PurgeFreesAllUnlocked) {
   RegisterAndUseAllocations();
 
-  PurgeAll();
+  MemoryPressureListener::NotifyMemoryPressure(
+      MemoryPressureListener::MEMORY_PRESSURE_CRITICAL);
+  RunLoop().RunUntilIdle();
 
   for (int i = 0; i < 3; ++i) {
     if (i == 0)
       EXPECT_TRUE(allocation(i)->is_locked());
     else
       EXPECT_EQ(LOCK_STATUS_PURGED, Lock(allocation(i)));
   }
 
   UnlockAndUnregisterAllocations();
 }
@@ skipping 122 matching lines @@
            Unretained(this)));
   memory_usage_thread_.message_loop()->PostTask(
       FROM_HERE,
       Bind(&ThreadedDiscardableMemoryManagerTest::SignalHelper,
            Unretained(this)));
   thread_sync_.Wait();
 }
 
 }  // namespace
 }  // namespace base