Add memory pressure listener to Blob storage

storage/browser/blob/blob_memory_controller_unittest.cc

Index: storage/browser/blob/blob_memory_controller_unittest.cc
diff --git a/storage/browser/blob/blob_memory_controller_unittest.cc b/storage/browser/blob/blob_memory_controller_unittest.cc
index 918315b378edc746ba125ccfe0b7b80807383151..bfe44b1f2ecd148d573f5c74b33e257663983803 100644
--- a/storage/browser/blob/blob_memory_controller_unittest.cc
+++ b/storage/browser/blob/blob_memory_controller_unittest.cc
@@ -33,6 +33,7 @@ const size_t kTestBlobStorageMaxSharedMemoryBytes = 50;
 const size_t kTestBlobStorageMaxBlobMemorySize = 500;
 const uint64_t kTestBlobStorageMaxDiskSpace = 1000;
 const uint64_t kTestBlobStorageMinFileSizeBytes = 10;
+const float kTestBlobStorageMinFileSizeBytesUnderPressure = 0.004;
 const uint64_t kTestBlobStorageMaxFileSizeBytes = 100;
 
 const uint64_t kTestSmallBlobStorageMaxDiskSpace = 100;
@@ -91,6 +92,8 @@ class BlobMemoryControllerTest : public testing::Test {
     limits.desired_max_disk_space = kTestBlobStorageMaxDiskSpace;
     limits.effective_max_disk_space = kTestBlobStorageMaxDiskSpace;
     limits.min_page_file_size = kTestBlobStorageMinFileSizeBytes;
+    limits.min_page_file_size_ratio_under_pressure =
+        kTestBlobStorageMinFileSizeBytesUnderPressure;
     limits.max_file_size = kTestBlobStorageMaxFileSizeBytes;
     controller->set_limits_for_testing(limits);
   }
@@ -103,6 +106,8 @@ class BlobMemoryControllerTest : public testing::Test {
     limits.desired_max_disk_space = kTestSmallBlobStorageMaxDiskSpace;
     limits.effective_max_disk_space = kTestSmallBlobStorageMaxDiskSpace;
     limits.min_page_file_size = kTestBlobStorageMinFileSizeBytes;
+    limits.min_page_file_size_ratio_under_pressure =
+        kTestBlobStorageMinFileSizeBytesUnderPressure;
     limits.max_file_size = kTestBlobStorageMaxFileSizeBytes;
     controller->set_limits_for_testing(limits);
   }
@@ -1120,4 +1125,47 @@ TEST_F(BlobMemoryControllerTest, DiskSpaceUnknown) {
   EXPECT_FALSE(controller.limits().IsDiskSpaceConstrained());
 }
 
+TEST_F(BlobMemoryControllerTest, OnMemoryPressure) {
+  BlobMemoryController controller(temp_dir_.GetPath(), file_runner_);
+  SetTestMemoryLimits(&controller);
+  AssertEnoughDiskSpace();
+
+  char kData[1];
+  kData[0] = 'e';
+
+  std::vector<scoped_refptr<ShareableBlobDataItem>> small_items;
+  size_t size_to_load = 2 * kTestBlobStorageMaxBlobMemorySize *
+                            kTestBlobStorageMinFileSizeBytesUnderPressure +
+                        1;
+  // 2 * kTestBlobStorageMinFileSizeBytesUnderPressure is less than
+  // 2 * kTestBlobStorageMinFileSizeBytes.
+  for (size_t i = 0; i < size_to_load; i++) {
+    BlobDataBuilder builder("fake");
+    builder.AppendData(kData, 1);
+    std::vector<scoped_refptr<ShareableBlobDataItem>> items =
+        CreateSharedDataItems(builder);
+    base::WeakPtr<QuotaAllocationTask> memory_task =
+        controller.ReserveMemoryQuota(items, GetMemoryRequestCallback());
+    EXPECT_FALSE(memory_task);
+    items[0]->set_state(ItemState::POPULATED_WITH_QUOTA);
+    small_items.insert(small_items.end(), items.begin(), items.end());
+  }
+  controller.NotifyMemoryItemsUsed(small_items);
+  EXPECT_FALSE(file_runner_->HasPendingTask());
+  EXPECT_EQ(size_to_load, controller.memory_usage());
+
+  controller.OnMemoryPressure(
+      base::MemoryPressureListener::MemoryPressureLevel::
+          MEMORY_PRESSURE_LEVEL_CRITICAL);
+
+  EXPECT_TRUE(file_runner_->HasPendingTask());
+  RunFileThreadTasks();
+
+  base::RunLoop().RunUntilIdle();
+
+  EXPECT_EQ(1u, controller.memory_usage());
+  EXPECT_EQ(size_to_load - 1, controller.disk_usage());
+  return;
+}
+
 }  // namespace storage