[BlobAsync] Asynchronous Blob Construction Final Patch

content/browser/blob_storage/blob_dispatcher_host_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 "content/browser/blob_storage/blob_dispatcher_host.h"
+
+#include <vector>
+
+#include "base/command_line.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/shared_memory.h"
+#include "base/run_loop.h"
+#include "base/tuple.h"
+#include "content/browser/fileapi/chrome_blob_storage_context.h"
+#include "content/common/fileapi/webblob_messages.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/test/test_browser_context.h"
+#include "content/public/test/test_browser_thread_bundle.h"
+#include "ipc/ipc_sender.h"
+#include "ipc/ipc_test_sink.h"
+#include "ipc/message_filter.h"
+#include "storage/browser/blob/blob_data_builder.h"
+#include "storage/browser/blob/blob_data_handle.h"
+#include "storage/browser/blob/blob_storage_context.h"
+#include "storage/common/blob_storage/blob_item_bytes_request.h"
+#include "storage/common/blob_storage/blob_item_bytes_response.h"
+#include "storage/common/data_element.h"
+#include "testing/gmock/include/gmock/gmock.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+using storage::BlobDataBuilder;
+using storage::BlobDataHandle;
+using storage::BlobItemBytesRequest;
+using storage::BlobItemBytesResponse;
+using storage::BlobStorageContext;
+using storage::BlobTransportResult;
+using storage::DataElement;
+using storage::IPCBlobCreationCancelCode;
+using RequestMemoryCallback =
+    storage::BlobAsyncBuilderHost::RequestMemoryCallback;
+
+namespace content {
+namespace {
+
+const char kContentType[] = "text/plain";
+const char kContentDisposition[] = "content_disposition";
+const char kData[] = "data!!";
+const size_t kDataSize = 6;
+
+const size_t kTestBlobStorageIPCThresholdBytes = 20;
+const size_t kTestBlobStorageMaxSharedMemoryBytes = 50;
+const uint64_t kTestBlobStorageMaxFileSizeBytes = 100;
+
+template <typename T>
+void SetPointerValue(T* pointer, T value) {
+  *pointer = value;
+}
+
+class TestableBlobDispatcherHost : public BlobDispatcherHost {
+ public:
+  TestableBlobDispatcherHost(ChromeBlobStorageContext* blob_storage_context,
+                             IPC::TestSink* sink)
+      : BlobDispatcherHost(blob_storage_context), sink_(sink) {
+    this->SetMemoryConstantsForTesting(kTestBlobStorageIPCThresholdBytes,
+                                       kTestBlobStorageMaxSharedMemoryBytes,
+                                       kTestBlobStorageMaxFileSizeBytes);
+  }
+
+  bool Send(IPC::Message* message) override { return sink_->Send(message); }
+
+  void ShutdownForBadMessage() override { shutdown_for_bad_message_ = true; }
+
+  bool shutdown_for_bad_message_ = false;
+  IPC::TestSink* sink_;
+
+ protected:
+  ~TestableBlobDispatcherHost() override {}
+
+ private:
+  friend class base::RefCountedThreadSafe<TestableBlobDispatcherHost>;
+};
+
+}  // namespace
+
+class BlobDispatcherHostTest : public testing::Test {
+ protected:
+  BlobDispatcherHostTest()
+      : browser_thread_bundle_(),
+        browser_context_(),
+        chrome_blob_storage_context_(
+            ChromeBlobStorageContext::GetFor(&browser_context_)) {
+    host_ =
+        new TestableBlobDispatcherHost(chrome_blob_storage_context_, &sink_);
+  }
+  ~BlobDispatcherHostTest() override {}
+
+  void SetUp() override {
+    base::CommandLine* command_line = base::CommandLine::ForCurrentProcess();
+    if (!command_line->HasSwitch(switches::kDisableKillAfterBadIPC)) {
+      command_line->AppendSwitch(switches::kDisableKillAfterBadIPC);
+    }
+    // We run the run loop to initialize the chrome blob storage context.
+    base::RunLoop().RunUntilIdle();
+    context_ = chrome_blob_storage_context_->context();
+    DCHECK(context_);
+  }
+
+  void ExpectBlobNotExist(const std::string& id) {
+    EXPECT_FALSE(context_->registry().HasEntry(id));
+    EXPECT_FALSE(host_->IsInUseInHost(id));
+    EXPECT_FALSE(IsBeingBuiltInHost(id));
+  }
+
+  void AsyncShortcutBlobTransfer(const std::string& id) {
+    sink_.ClearMessages();
+    ExpectBlobNotExist(id);
+    host_->OnRegisterBlobUUID(id, std::string(kContentType),
+                              std::string(kContentDisposition),
+                              std::set<std::string>());
+    EXPECT_FALSE(host_->shutdown_for_bad_message_);
+    DataElement element;
+    element.SetToBytes(kData, kDataSize);
+    std::vector<DataElement> elements = {element};
+    host_->OnStartBuildingBlob(id, elements);
+    EXPECT_FALSE(host_->shutdown_for_bad_message_);
+    ExpectDone(id);
+    sink_.ClearMessages();
+  }
+
+  void AsyncBlobTransfer(const std::string& id) {
+    sink_.ClearMessages();
+    ExpectBlobNotExist(id);
+    host_->OnRegisterBlobUUID(id, std::string(kContentType),
+                              std::string(kContentDisposition),
+                              std::set<std::string>());
+    EXPECT_FALSE(host_->shutdown_for_bad_message_);
+    DataElement element;
+    element.SetToBytesDescription(kDataSize);
+    std::vector<DataElement> elements = {element};
+    host_->OnStartBuildingBlob(id, elements);
+    EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+    // Expect our request.
+    std::vector<BlobItemBytesRequest> expected_requests = {
+        BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize)};
+    ExpectRequest(id, expected_requests);
+    sink_.ClearMessages();
+
+    // Send results;
+    BlobItemBytesResponse response(0);
+    std::memcpy(response.allocate_mutable_data(kDataSize), kData, kDataSize);
+    std::vector<BlobItemBytesResponse> responses = {response};
+    host_->OnMemoryItemResponse(id, responses);
+    ExpectDone(id);
+    sink_.ClearMessages();
+  }
+
+  void ExpectAndResetBadMessage() {
+    EXPECT_TRUE(host_->shutdown_for_bad_message_);
+    host_->shutdown_for_bad_message_ = false;
+  }
+
+  void ExpectHandleEqualsData(BlobDataHandle* handle,
+                              const std::vector<DataElement>& data) {
+    scoped_ptr<storage::BlobDataSnapshot> snapshot = handle->CreateSnapshot();
+    EXPECT_FALSE(handle->IsBeingBuilt());
+    for (size_t i = 0; i < data.size(); i++) {
+      const DataElement& expected = data[i];
+      const DataElement& actual = snapshot->items()[i]->data_element();
+      EXPECT_EQ(expected, actual);
+    }
+    EXPECT_EQ(data.size(), snapshot->items().size());
+  }
+
+  void ExpectRequest(
+      const std::string& expected_uuid,
+      const std::vector<BlobItemBytesRequest>& expected_requests) {
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_DoneBuildingBlob::ID));
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_CancelBuildingBlob::ID));
+    const IPC::Message* message =
+        sink_.GetUniqueMessageMatching(BlobStorageMsg_RequestMemoryItem::ID);
+    ASSERT_TRUE(message);
+    base::Tuple<std::string, std::vector<storage::BlobItemBytesRequest>,
+                std::vector<base::SharedMemoryHandle>,
+                std::vector<IPC::PlatformFileForTransit>>
+        args;
+    BlobStorageMsg_RequestMemoryItem::Read(message, &args);
+    EXPECT_EQ(expected_uuid, base::get<0>(args));
+    std::vector<BlobItemBytesRequest> requests = base::get<1>(args);
+    ASSERT_EQ(requests.size(), expected_requests.size());
+    for (size_t i = 0; i < expected_requests.size(); ++i) {
+      EXPECT_EQ(expected_requests[i], requests[i]);
+    }
+  }
+
+  void ExpectRequestWithSharedMemoryHandles(
+      const std::string& expected_uuid,
+      const std::vector<BlobItemBytesRequest>& expected_requests,
+      std::vector<base::SharedMemoryHandle>* shared_memory_handles) {
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_DoneBuildingBlob::ID));
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_CancelBuildingBlob::ID));
+    const IPC::Message* message =
+        sink_.GetUniqueMessageMatching(BlobStorageMsg_RequestMemoryItem::ID);
+    ASSERT_TRUE(message);
+    base::Tuple<std::string, std::vector<storage::BlobItemBytesRequest>,
+                std::vector<base::SharedMemoryHandle>,
+                std::vector<IPC::PlatformFileForTransit>>
+        args;
+    BlobStorageMsg_RequestMemoryItem::Read(message, &args);
+    EXPECT_EQ(expected_uuid, base::get<0>(args));
+    std::vector<BlobItemBytesRequest> requests = base::get<1>(args);
+    ASSERT_EQ(requests.size(), expected_requests.size());
+    for (size_t i = 0; i < expected_requests.size(); ++i) {
+      EXPECT_EQ(expected_requests[i], requests[i]);
+    }
+    *shared_memory_handles = std::move(base::get<2>(args));
+  }
+
+  void ExpectCancel(const std::string& expected_uuid,
+                    IPCBlobCreationCancelCode code) {
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_RequestMemoryItem::ID));
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_DoneBuildingBlob::ID));
+    const IPC::Message* message =
+        sink_.GetUniqueMessageMatching(BlobStorageMsg_CancelBuildingBlob::ID);
+    ASSERT_TRUE(message);
+    base::Tuple<std::string, IPCBlobCreationCancelCode> args;
+    BlobStorageMsg_CancelBuildingBlob::Read(message, &args);
+    EXPECT_EQ(expected_uuid, base::get<0>(args));
+    EXPECT_EQ(code, base::get<1>(args));
+  }
+
+  void ExpectDone(const std::string& expected_uuid) {
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_RequestMemoryItem::ID));
+    EXPECT_FALSE(
+        sink_.GetFirstMessageMatching(BlobStorageMsg_CancelBuildingBlob::ID));
+    const IPC::Message* message =
+        sink_.GetUniqueMessageMatching(BlobStorageMsg_DoneBuildingBlob::ID);
+    base::Tuple<std::string> args;
+    BlobStorageMsg_DoneBuildingBlob::Read(message, &args);
+    EXPECT_EQ(expected_uuid, base::get<0>(args));
+  }
+
+  bool IsBeingBuiltInHost(const std::string& uuid) {
+    return host_->async_builder_.IsBeingBuilt(uuid);
+  }
+
+  IPC::TestSink sink_;
+  TestBrowserThreadBundle browser_thread_bundle_;
+  TestBrowserContext browser_context_;
+  ChromeBlobStorageContext* chrome_blob_storage_context_;
+  BlobStorageContext* context_ = nullptr;
+  scoped_refptr<TestableBlobDispatcherHost> host_;
+};
+
+TEST_F(BlobDispatcherHostTest, EmptyUUIDs) {
+  host_->OnRegisterBlobUUID("", "", "", std::set<std::string>());
+  ExpectAndResetBadMessage();
+  host_->OnStartBuildingBlob("", std::vector<DataElement>());
+  ExpectAndResetBadMessage();
+  host_->OnMemoryItemResponse("", std::vector<BlobItemBytesResponse>());
+  ExpectAndResetBadMessage();
+  host_->OnCancelBuildingBlob("", IPCBlobCreationCancelCode::UNKNOWN);
+  ExpectAndResetBadMessage();
+}
+
+TEST_F(BlobDispatcherHostTest, Shortcut) {
+  const std::string kId = "uuid1";
+  AsyncShortcutBlobTransfer(kId);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  scoped_ptr<BlobDataHandle> handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle);
+
+  DataElement expected;
+  expected.SetToBytes(kData, kDataSize);
+  std::vector<DataElement> elements = {expected};
+  ExpectHandleEqualsData(handle.get(), elements);
+}
+
+TEST_F(BlobDispatcherHostTest, RegularTransfer) {
+  const std::string kId = "uuid1";
+  AsyncBlobTransfer(kId);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  scoped_ptr<BlobDataHandle> handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle);
+
+  DataElement expected;
+  expected.SetToBytes(kData, kDataSize);
+  std::vector<DataElement> elements = {expected};
+  ExpectHandleEqualsData(handle.get(), elements);
+}
+
+TEST_F(BlobDispatcherHostTest, SharedMemoryTransfer) {
+  const std::string kId = "uuid1";
+  const size_t kLargeSize = kTestBlobStorageMaxSharedMemoryBytes * 2;
+  std::vector<base::SharedMemoryHandle> shared_memory_handles;
+
+  ExpectBlobNotExist(kId);
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  // Grab the handle.
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  bool built = false;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+  EXPECT_FALSE(built);
+
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  DataElement element;
+  element.SetToBytesDescription(kLargeSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+  // Expect our first request.
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateSharedMemoryRequest(
+          0 /* request_number */, 0 /* renderer_item_index */,
+          0 /* renderer_item_offset */,
+          static_cast<uint64_t>(
+              kTestBlobStorageMaxSharedMemoryBytes) /* size */,
+          0 /* handle_index */, 0 /* handle_offset */)};
+  ExpectRequestWithSharedMemoryHandles(kId, expected_requests,
+                                       &shared_memory_handles);
+  sink_.ClearMessages();
+
+  // Populate the shared memory.
+  EXPECT_EQ(1u, shared_memory_handles.size());
+  EXPECT_TRUE(base::SharedMemory::IsHandleValid(shared_memory_handles[0]));
+  {
+    base::SharedMemory memory(
+        base::SharedMemory::DuplicateHandle(shared_memory_handles[0]), false);
+    memory.Map(kTestBlobStorageMaxSharedMemoryBytes);
+    std::memset(memory.memory(), 'X', kTestBlobStorageMaxSharedMemoryBytes);
+    memory.Close();
+  }
+
+  // Send the confirmation.
+  std::vector<BlobItemBytesResponse> responses = {BlobItemBytesResponse(0)};
+  host_->OnMemoryItemResponse(kId, responses);
+
+  // Expect our second request.
+  expected_requests = {BlobItemBytesRequest::CreateSharedMemoryRequest(
+      1 /* request_number */, 0 /* renderer_item_index */,
+      static_cast<uint64_t>(
+          kTestBlobStorageMaxSharedMemoryBytes) /* renderer_item_offset */,
+      static_cast<uint64_t>(kTestBlobStorageMaxSharedMemoryBytes) /* size */,
+      0 /* handle_index */, 0 /* handle_offset */)};
+  ExpectRequestWithSharedMemoryHandles(kId, expected_requests,
+                                       &shared_memory_handles);
+  sink_.ClearMessages();
+
+  // Populate the shared memory.
+  EXPECT_EQ(1u, shared_memory_handles.size());
+  EXPECT_TRUE(base::SharedMemory::IsHandleValid(shared_memory_handles[0]));
+  {
+    base::SharedMemory memory(
+        base::SharedMemory::DuplicateHandle(shared_memory_handles[0]), false);
+    memory.Map(kTestBlobStorageMaxSharedMemoryBytes);
+    std::memset(memory.memory(), 'Z', kTestBlobStorageMaxSharedMemoryBytes);
+    memory.Close();
+  }
+  // Send the confirmation.
+  responses = {BlobItemBytesResponse(1)};
+  host_->OnMemoryItemResponse(kId, responses);
+
+  ExpectDone(kId);
+  sink_.ClearMessages();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(built);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  scoped_ptr<BlobDataHandle> handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle);
+
+  DataElement expected;
+  expected.SetToAllocatedBytes(kLargeSize / 2);
+  std::memset(expected.mutable_bytes(), 'X', kLargeSize / 2);
+  elements = {expected};
+  std::memset(expected.mutable_bytes(), 'Z', kLargeSize / 2);
+  elements.push_back(expected);
+  ExpectHandleEqualsData(handle.get(), elements);
+}
+
+TEST_F(BlobDispatcherHostTest, OnCancelBuildingBlob) {
+  const std::string kId("id");
+  // We ignore blobs that are unknown, as it could have been cancelled earlier
+  // and the renderer didn't know about it yet.
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+  // Start building blob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  // It should have requested memory here.
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  sink_.ClearMessages();
+
+  // Cancel in middle of construction.
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(host_->IsInUseInHost(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+  // Check that's it's broken.
+  scoped_ptr<BlobDataHandle> handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle->IsBroken());
+  handle.reset();
+  base::RunLoop().RunUntilIdle();
+
+  // Get rid of it in the host.
+  host_->OnDecrementBlobRefCount(kId);
+  ExpectBlobNotExist(kId);
+
+  // Create blob again to verify we don't have any old construction state lying
+  // around.
+  AsyncBlobTransfer(kId);
+
+  // Check data.
+  handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle);
+  DataElement expected;
+  expected.SetToBytes(kData, kDataSize);
+  std::vector<DataElement> expecteds = {expected};
+  ExpectHandleEqualsData(handle.get(), expecteds);
+
+  // Verify we can't cancel after the fact.
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  ExpectAndResetBadMessage();
+}
+
+TEST_F(BlobDispatcherHostTest, BlobDataWithHostDeletion) {
+  // Build up a basic blob.
+  const std::string kId("id");
+  AsyncShortcutBlobTransfer(kId);
+  scoped_ptr<BlobDataHandle> handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(handle);
+
+  // Kill the host.
+  host_ = nullptr;
+  base::RunLoop().RunUntilIdle();
+  // Should still be there due to the handle.
+  scoped_ptr<BlobDataHandle> another_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(another_handle);
+
+  // Should disappear after dropping both handles.
+  handle.reset();
+  another_handle.reset();
+  base::RunLoop().RunUntilIdle();
+
+  handle = context_->GetBlobDataFromUUID(kId);
+  EXPECT_FALSE(handle);
+}
+
+TEST_F(BlobDispatcherHostTest, BlobReferenceWhileConstructing) {
+  const std::string kId("id");
+
+  // Start building blob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  // Grab the handle.
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(blob_data_handle);
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  bool built = false;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+
+  // Continue building.
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  sink_.ClearMessages();
+
+  // Send data.
+  BlobItemBytesResponse response(0);
+  std::memcpy(response.allocate_mutable_data(kDataSize), kData, kDataSize);
+  std::vector<BlobItemBytesResponse> responses = {response};
+  sink_.ClearMessages();
+  host_->OnMemoryItemResponse(kId, responses);
+
+  ExpectDone(kId);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(built);
+}
+
+TEST_F(BlobDispatcherHostTest, BlobReferenceWhileShortcutConstructing) {
+  const std::string kId("id");
+
+  // Start building blob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  // Grab the handle.
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(blob_data_handle);
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  bool built = false;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+
+  // Continue building.
+  DataElement element;
+  element.SetToBytes(kData, kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  ExpectDone(kId);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(built);
+}
+
+TEST_F(BlobDispatcherHostTest, BlobReferenceWhileConstructingCancelled) {
+  const std::string kId("id");
+
+  // Start building blob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  // Grab the handle.
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(blob_data_handle);
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  bool built = true;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+
+  // Cancel in middle of construction.
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(host_->IsInUseInHost(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+  EXPECT_TRUE(blob_data_handle->IsBroken());
+  EXPECT_FALSE(built);
+  built = true;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+  EXPECT_FALSE(built);
+
+  // Remove it.
+  blob_data_handle.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  host_->OnDecrementBlobRefCount(kId);
+  ExpectBlobNotExist(kId);
+}
+
+TEST_F(BlobDispatcherHostTest, DecrementRefAfterRegister) {
+  const std::string kId("id");
+  // Decrement the refcount while building (renderer blob gc'd before
+  // construction was completed).
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+  ExpectCancel(kId,
+               IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING);
+  sink_.ClearMessages();
+
+  // Do the same, but this time grab a handle before we decrement.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(IsBeingBuiltInHost(kId));
+
+  // Finish up the blob, and verify we got the done message.
+  DataElement element;
+  element.SetToBytes(kData, kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  ExpectDone(kId);
+  sink_.ClearMessages();
+  // Get rid of the handle, and verify it's gone.
+  blob_data_handle.reset();
+  base::RunLoop().RunUntilIdle();
+  // Check that it's no longer around.
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, DecrementRefAfterOnStart) {
+  const std::string kId("id");
+
+  // Decrement the refcount while building, after we call OnStartBuildlingBlob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize)};
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+  ExpectCancel(kId,
+               IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING);
+  sink_.ClearMessages();
+
+  // Do the same, but this time grab a handle to keep it alive.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  // Grab the handle before decrementing.
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(IsBeingBuiltInHost(kId));
+
+  // We finish the blob, and verify that we send 'Done' back to the renderer.
+  BlobItemBytesResponse response(0);
+  std::memcpy(response.allocate_mutable_data(kDataSize), kData, kDataSize);
+  std::vector<BlobItemBytesResponse> responses = {response};
+  host_->OnMemoryItemResponse(kId, responses);
+  ExpectDone(kId);
+  sink_.ClearMessages();
+  // Check that it's still around.
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+
+  // Get rid of the handle, and verify it's gone.
+  blob_data_handle.reset();
+  base::RunLoop().RunUntilIdle();
+  // Check that it's no longer around.
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, DecrementRefAfterOnStartWithHandle) {
+  const std::string kId("id");
+  // Case 3: Decrement the refcount while building, after we call
+  // OnStartBuildlingBlob, except we have another handle.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  bool built = true;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+
+  // Check that we got the expected request.
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize)};
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(IsBeingBuiltInHost(kId));
+  // Decrement, simulating where the ref goes out of scope in renderer.
+  host_->OnDecrementBlobRefCount(kId);
+  // We still have the blob as it's not done.
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  EXPECT_TRUE(IsBeingBuiltInHost(kId));
+  // Cancel to clean up.
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  // Run loop to propagate the handle decrement in the host.
+  base::RunLoop().RunUntilIdle();
+  // We still have the entry because of our earlier handle.
+  EXPECT_TRUE(context_->registry().HasEntry(kId));
+  EXPECT_FALSE(IsBeingBuiltInHost(kId));
+  sink_.ClearMessages();
+
+  // Should disappear after dropping the handle.
+  EXPECT_TRUE(blob_data_handle->IsBroken());
+  blob_data_handle.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, HostDisconnectAfterRegisterWithHandle) {
+  const std::string kId("id");
+
+  // Delete host with a handle to the blob.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  scoped_ptr<BlobDataHandle> blob_data_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(blob_data_handle->IsBeingBuilt());
+  bool built = true;
+  blob_data_handle->RunOnConstructionComplete(
+      base::Bind(&SetPointerValue<bool>, &built));
+  // Get rid of host, which was doing the constructing.
+  host_ = nullptr;
+  EXPECT_FALSE(blob_data_handle->IsBeingBuilt());
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(built);
+
+  // Should still be there due to the handle.
+  scoped_ptr<BlobDataHandle> another_handle =
+      context_->GetBlobDataFromUUID(kId);
+  EXPECT_TRUE(another_handle);
+
+  // Should disappear after dropping both handles.
+  blob_data_handle.reset();
+  another_handle.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, HostDisconnectAfterOnStart) {
+  const std::string kId("id");
+
+  // Host deleted after OnStartBuilding.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  host_->OnStartBuildingBlob(kId, elements);
+
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize)};
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+  host_ = nullptr;
+  // We need to run the message loop because of the handle in the async builder.
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, HostDisconnectAfterOnMemoryResponse) {
+  const std::string kId("id");
+
+  // Host deleted after OnMemoryItemResponse.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+
+  // Create list of two items.
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element, element};
+  host_->OnStartBuildingBlob(kId, elements);
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize),
+      BlobItemBytesRequest::CreateIPCRequest(1, 1, 0, kDataSize)};
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+
+  // Send just one response so the blob isn't 'done' yet.
+  BlobItemBytesResponse response(0);
+  std::memcpy(response.allocate_mutable_data(kDataSize), kData, kDataSize);
+  std::vector<BlobItemBytesResponse> responses = {response};
+  host_->OnMemoryItemResponse(kId, responses);
+  EXPECT_EQ(0u, sink_.message_count());
+
+  host_ = nullptr;
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+}
+
+TEST_F(BlobDispatcherHostTest, CreateBlobWithBrokenReference) {
+  const std::string kBrokenId("id1");
+  const std::string kReferencingId("id2");
+
+  // First, let's test a circular reference.
+  const std::string kCircularId("id1");
+  host_->OnRegisterBlobUUID(kCircularId, std::string(kContentType),
+                            std::string(kContentDisposition), {kCircularId});
+  ExpectAndResetBadMessage();
+
+  // Next, test a blob that references a broken blob.
+  host_->OnRegisterBlobUUID(kBrokenId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  host_->OnCancelBuildingBlob(kBrokenId, IPCBlobCreationCancelCode::UNKNOWN);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  EXPECT_TRUE(context_->GetBlobDataFromUUID(kBrokenId)->IsBroken());
+
+  // Create referencing blob. We should be broken right away, but also ignore
+  // the subsequent OnStart message.
+  host_->OnRegisterBlobUUID(kReferencingId, std::string(kContentType),
+                            std::string(kContentDisposition), {kBrokenId});
+  EXPECT_TRUE(context_->GetBlobDataFromUUID(kReferencingId)->IsBroken());
+  EXPECT_FALSE(IsBeingBuiltInHost(kReferencingId));
+  EXPECT_TRUE(context_->registry().HasEntry(kReferencingId));
+  ExpectCancel(kReferencingId,
+               IPCBlobCreationCancelCode::REFERENCED_BLOB_BROKEN);
+  sink_.ClearMessages();
+
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  element.SetToBlob(kBrokenId);
+  elements.push_back(element);
+  host_->OnStartBuildingBlob(kReferencingId, elements);
+  EXPECT_EQ(0u, sink_.message_count());
+  base::RunLoop().RunUntilIdle();
+}
+
+TEST_F(BlobDispatcherHostTest, DeferenceBlobOnDifferentHost) {
+  const std::string kId("id");
+  // Data elements for our transfer & checking messages.
+  DataElement element;
+  element.SetToBytesDescription(kDataSize);
+  std::vector<DataElement> elements = {element};
+  std::vector<BlobItemBytesRequest> expected_requests = {
+      BlobItemBytesRequest::CreateIPCRequest(0, 0, 0, kDataSize)};
+  BlobItemBytesResponse response(0);
+  std::memcpy(response.allocate_mutable_data(kDataSize), kData, kDataSize);
+  std::vector<BlobItemBytesResponse> responses = {response};
+
+  scoped_refptr<TestableBlobDispatcherHost> host2(
+      new TestableBlobDispatcherHost(chrome_blob_storage_context_, &sink_));
+
+  // Delete host with another host having a referencing, then dereference on
+  // second host. Verify we're still building it on first host, and then
+  // verify that a building message from the renderer will kill it.
+
+  // Test OnStartBuilding after double dereference.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  host2->OnIncrementBlobRefCount(kId);
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_FALSE(host_->IsInUseInHost(kId));
+  host2->OnDecrementBlobRefCount(kId);
+  // So no more blob in the context, but we're still being built in host 1.
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(host_->async_builder_.IsBeingBuilt(kId));
+  host_->OnStartBuildingBlob(kId, elements);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  // We should be cleaned up.
+  EXPECT_FALSE(host_->async_builder_.IsBeingBuilt(kId));
+  ExpectCancel(kId,
+               IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING);
+  sink_.ClearMessages();
+
+  // Same as above, but test OnMemoryItemResponse after double dereference.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  host2->OnIncrementBlobRefCount(kId);
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_FALSE(host_->IsInUseInHost(kId));
+  host_->OnStartBuildingBlob(kId, elements);
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+
+  host2->OnDecrementBlobRefCount(kId);
+  // So no more blob in the context, but we're still being built in host 1.
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(host_->async_builder_.IsBeingBuilt(kId));
+  host_->OnMemoryItemResponse(kId, responses);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  // We should be cleaned up.
+  EXPECT_FALSE(host_->async_builder_.IsBeingBuilt(kId));
+  ExpectCancel(kId,
+               IPCBlobCreationCancelCode::BLOB_DEREFERENCED_WHILE_BUILDING);
+  sink_.ClearMessages();
+
+  // Same, but now for OnCancel.
+  host_->OnRegisterBlobUUID(kId, std::string(kContentType),
+                            std::string(kContentDisposition),
+                            std::set<std::string>());
+  host2->OnIncrementBlobRefCount(kId);
+  host_->OnDecrementBlobRefCount(kId);
+  EXPECT_FALSE(host_->IsInUseInHost(kId));
+  host_->OnStartBuildingBlob(kId, elements);
+  ExpectRequest(kId, expected_requests);
+  sink_.ClearMessages();
+
+  host2->OnDecrementBlobRefCount(kId);
+  // So no more blob in the context, but we're still being built in host 1.
+  EXPECT_FALSE(context_->registry().HasEntry(kId));
+  EXPECT_TRUE(host_->async_builder_.IsBeingBuilt(kId));
+  host_->OnCancelBuildingBlob(kId, IPCBlobCreationCancelCode::UNKNOWN);
+  EXPECT_FALSE(host_->shutdown_for_bad_message_);
+  // We should be cleaned up.
+  EXPECT_FALSE(host_->async_builder_.IsBeingBuilt(kId));
+}
+
+}  // namespace content