Fix various issues in RedirectToFileResourceHandler.

content/browser/loader/resource_loader_unittest.cc

 // Copyright (c) 2013 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/loader/resource_loader.h"
 
+#include "base/file_util.h"
+#include "base/message_loop/message_loop_proxy.h"
+#include "base/platform_file.h"
 #include "base/run_loop.h"
 #include "content/browser/browser_thread_impl.h"
+#include "content/browser/loader/redirect_to_file_resource_handler.h"
 #include "content/browser/loader/resource_loader_delegate.h"
 #include "content/public/browser/resource_request_info.h"
+#include "content/public/common/resource_response.h"
 #include "content/public/test/mock_resource_context.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "content/test/test_content_browser_client.h"
 #include "ipc/ipc_message.h"
+#include "net/base/mock_file_stream.h"
 #include "net/base/request_priority.h"
 #include "net/cert/x509_certificate.h"
 #include "net/ssl/client_cert_store.h"
 #include "net/ssl/ssl_cert_request_info.h"
 #include "net/url_request/url_request.h"
+#include "net/url_request/url_request_job_factory_impl.h"
+#include "net/url_request/url_request_test_job.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
+#include "webkit/common/blob/shareable_file_reference.h"
+
+using webkit_blob::ShareableFileReference;
 
 namespace content {
 namespace {
 
 // Stub client certificate store that returns a preset list of certificates for
 // each request and records the arguments of the most recent request for later
 // inspection.
 class ClientCertStoreStub : public net::ClientCertStore {
  public:
   ClientCertStoreStub(const net::CertificateList& certs)
@@ skipping 30 matching lines @@
  private:
   const net::CertificateList response_;
   int request_count_;
   std::vector<std::string> requested_authorities_;
 };
 
 // Dummy implementation of ResourceHandler, instance of which is needed to
 // initialize ResourceLoader.
 class ResourceHandlerStub : public ResourceHandler {
  public:
-  ResourceHandlerStub() : ResourceHandler(NULL) {}
+  explicit ResourceHandlerStub(net::URLRequest* request)
+      : ResourceHandler(request),
+        defer_start_(false),
+        received_response_completed_(false),
+        total_bytes_downloaded_(0) {
+  }
 
+  void set_defer_start(bool defer_start) { defer_start_ = defer_start; }
+
+  const GURL& start_url() const { return start_url_; }
+  ResourceResponse* response() const { return response_.get(); }
+  bool received_response_completed() const {
+    return received_response_completed_;
+  }
+  const net::URLRequestStatus& status() const { return status_; }
+  int total_bytes_downloaded() const { return total_bytes_downloaded_; }
+
+  void Resume() {
+    controller()->Resume();
+  }
+
+  // ResourceHandler implementation:
   virtual bool OnUploadProgress(int request_id,
                                 uint64 position,
                                 uint64 size) OVERRIDE {
+    NOTREACHED();
     return true;
   }
 
   virtual bool OnRequestRedirected(int request_id,
                                    const GURL& url,
                                    ResourceResponse* response,
                                    bool* defer) OVERRIDE {
+    NOTREACHED();
     return true;
   }
 
   virtual bool OnResponseStarted(int request_id,
                                  ResourceResponse* response,
-                                 bool* defer) OVERRIDE { return true; }
+                                 bool* defer) OVERRIDE {
+    EXPECT_FALSE(response_);
+    response_ = response;
+    return true;
+  }
 
   virtual bool OnWillStart(int request_id,
                            const GURL& url,
                            bool* defer) OVERRIDE {
+    EXPECT_TRUE(start_url_.is_empty());
+    start_url_ = url;
+    *defer = defer_start_;
     return true;
   }
 
   virtual bool OnWillRead(int request_id,
                           scoped_refptr<net::IOBuffer>* buf,
                           int* buf_size,
                           int min_size) OVERRIDE {
-    return true;
+    NOTREACHED();
+    return false;
   }
 
   virtual bool OnReadCompleted(int request_id,
                                int bytes_read,
                                bool* defer) OVERRIDE {
-    return true;
+    NOTREACHED();
+    return false;
   }
 
   virtual void OnResponseCompleted(int request_id,
                                    const net::URLRequestStatus& status,
                                    const std::string& security_info,
                                    bool* defer) OVERRIDE {
+    // TODO(davidben): This DCHECK currently fires everywhere. Fix the places in
+    // ResourceLoader where OnResponseCompleted is signaled twice.
+    // DCHECK(!received_response_completed_);
+    received_response_completed_ = true;
+    status_ = status;
   }
 
   virtual void OnDataDownloaded(int request_id,
-                                int bytes_downloaded) OVERRIDE {}
+                                int bytes_downloaded) OVERRIDE {
+    total_bytes_downloaded_ += bytes_downloaded;
+  }
+
+ private:
+  bool defer_start_;
+  GURL start_url_;
+  scoped_refptr<ResourceResponse> response_;
+  bool received_response_completed_;
+  net::URLRequestStatus status_;
+  int total_bytes_downloaded_;
 };
 
 // Test browser client that captures calls to SelectClientCertificates and
 // records the arguments of the most recent call for later inspection.
 class SelectCertificateBrowserClient : public TestContentBrowserClient {
  public:
   SelectCertificateBrowserClient() : call_count_(0) {}
 
   virtual void SelectClientCertificate(
       int render_process_id,
@@ skipping 28 matching lines @@
   }
 
   void SetClientCertStore(scoped_ptr<net::ClientCertStore> store) {
     dummy_cert_store_ = store.Pass();
   }
 
  private:
   scoped_ptr<net::ClientCertStore> dummy_cert_store_;
 };
 
+// Fails to create a temporary file with the given error.
+void CreateTemporaryError(
+    base::PlatformFileError error,
+    const CreateTemporaryFileStreamCallback& callback) {
+  scoped_ptr<net::FileStream> null_stream;
+  base::MessageLoop::current()->PostTask(
+      FROM_HERE,
+      base::Bind(callback, error, base::Passed(&null_stream),
+                 scoped_refptr<ShareableFileReference>()));
+}
+
+class MockTemporaryFileStream {
+ public:
+  MockTemporaryFileStream() {
+    base::FilePath file_path;
+    CHECK(base::CreateTemporaryFile(&file_path));
+    base::PlatformFile platform_file =
+        base::CreatePlatformFile(file_path,
+                                 base::PLATFORM_FILE_WRITE |
+                                 base::PLATFORM_FILE_TEMPORARY |
+                                 base::PLATFORM_FILE_CREATE_ALWAYS |
+                                 base::PLATFORM_FILE_ASYNC,
+                                 NULL, NULL);
+    CHECK_NE(base::kInvalidPlatformFileValue, platform_file);
+    file_stream_.reset(
+        new net::testing::MockFileStream(
+            platform_file,
+            base::PLATFORM_FILE_WRITE | base::PLATFORM_FILE_ASYNC,
+            NULL, base::MessageLoopProxy::current()));
+    deletable_file_ =
+        ShareableFileReference::GetOrCreate(
+            file_path,
+            ShareableFileReference::DELETE_ON_FINAL_RELEASE,
+            BrowserThread::GetMessageLoopProxyForThread(
+                BrowserThread::FILE).get());
+  }
+
+  net::testing::MockFileStream* file_stream() const {
+    return file_stream_.get();
+  }
+  ShareableFileReference* deletable_file() const {
+    return deletable_file_.get();
+  }
+
+  RedirectToFileResourceHandler::CreateTemporaryCB Callback() {
+    return base::Bind(&MockTemporaryFileStream::PostCallback,
+                      base::Unretained(this));
+  }
+
+ private:
+  void PostCallback(const CreateTemporaryFileStreamCallback& callback) {
+    DCHECK(file_stream_);
+    DCHECK(deletable_file_);
+    scoped_ptr<net::FileStream> file_stream =
+        file_stream_.PassAs<net::FileStream>();
+    base::MessageLoop::current()->PostTask(
+        FROM_HERE,
+        base::Bind(callback, base::PLATFORM_FILE_OK,
+                   base::Passed(&file_stream), deletable_file_));
+    deletable_file_ = NULL;
+  }
+
+  scoped_ptr<net::testing::MockFileStream> file_stream_;
+  scoped_refptr<ShareableFileReference> deletable_file_;
+};
+
 }  // namespace
 
 class ResourceLoaderTest : public testing::Test,
                            public ResourceLoaderDelegate {
  protected:
   ResourceLoaderTest()
     : thread_bundle_(content::TestBrowserThreadBundle::IO_MAINLOOP),
       resource_context_(&test_url_request_context_) {
+    job_factory_.SetProtocolHandler(
+        "test", net::URLRequestTestJob::CreateProtocolHandler());
+    test_url_request_context_.set_job_factory(&job_factory_);
+  }
+
+  scoped_ptr<net::URLRequest> CreateTestRequest(const GURL& url) {
+    const int kRenderProcessId = 1;
+    const int kRenderViewId = 2;
+
+    scoped_ptr<net::URLRequest> request(
+        new net::URLRequest(url, net::DEFAULT_PRIORITY, NULL,
+                            resource_context_.GetRequestContext()));
+    ResourceRequestInfo::AllocateForTesting(request.get(),
+                                            ResourceType::MAIN_FRAME,
+                                            &resource_context_,
+                                            kRenderProcessId,
+                                            kRenderViewId,
+                                            MSG_ROUTING_NONE,
+                                            false);
+    return request.Pass();
   }
 
   // ResourceLoaderDelegate:
   virtual ResourceDispatcherHostLoginDelegate* CreateLoginDelegate(
       ResourceLoader* loader,
       net::AuthChallengeInfo* auth_info) OVERRIDE {
     return NULL;
   }
   virtual bool AcceptAuthRequest(
       ResourceLoader* loader,
@@ skipping 10 matching lines @@
     return false;
   }
   virtual void DidStartRequest(ResourceLoader* loader) OVERRIDE {}
   virtual void DidReceiveRedirect(ResourceLoader* loader,
                                   const GURL& new_url) OVERRIDE {}
   virtual void DidReceiveResponse(ResourceLoader* loader) OVERRIDE {}
   virtual void DidFinishLoading(ResourceLoader* loader) OVERRIDE {}
 
   content::TestBrowserThreadBundle thread_bundle_;
 
+  net::URLRequestJobFactoryImpl job_factory_;
   net::TestURLRequestContext test_url_request_context_;
   ResourceContextStub resource_context_;
 };
 
 // Verifies if a call to net::UrlRequest::Delegate::OnCertificateRequested()
 // causes client cert store to be queried for certificates and if the returned
 // certificates are correctly passed to the content browser client for
 // selection.
 TEST_F(ResourceLoaderTest, ClientCertStoreLookup) {
-  const int kRenderProcessId = 1;
-  const int kRenderViewId = 2;
-
-  scoped_ptr<net::URLRequest> request(
-      new net::URLRequest(GURL("dummy"),
-                          net::DEFAULT_PRIORITY,
-                          NULL,
-                          resource_context_.GetRequestContext()));
-  ResourceRequestInfo::AllocateForTesting(request.get(),
-                                          ResourceType::MAIN_FRAME,
-                                          &resource_context_,
-                                          kRenderProcessId,
-                                          kRenderViewId,
-                                          MSG_ROUTING_NONE,
-                                          false);
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(GURL("dummy"));
 
   // Set up the test client cert store.
   net::CertificateList dummy_certs(1, scoped_refptr<net::X509Certificate>(
       new net::X509Certificate("test", "test", base::Time(), base::Time())));
   scoped_ptr<ClientCertStoreStub> test_store(
       new ClientCertStoreStub(dummy_certs));
   EXPECT_EQ(0, test_store->request_count());
 
   // Ownership of the |request| and |test_store| is about to be turned over to
   // ResourceLoader. We need to keep raw pointer copies to access these objects
   // later.
   net::URLRequest* raw_ptr_to_request = request.get();
   ClientCertStoreStub* raw_ptr_to_store = test_store.get();
   resource_context_.SetClientCertStore(
       test_store.PassAs<net::ClientCertStore>());
 
-  scoped_ptr<ResourceHandler> resource_handler(new ResourceHandlerStub());
+  scoped_ptr<ResourceHandler> resource_handler(
+      new ResourceHandlerStub(request.get()));
   ResourceLoader loader(request.Pass(), resource_handler.Pass(), this);
 
   // Prepare a dummy certificate request.
   scoped_refptr<net::SSLCertRequestInfo> cert_request_info(
       new net::SSLCertRequestInfo());
   std::vector<std::string> dummy_authority(1, "dummy");
   cert_request_info->cert_authorities = dummy_authority;
 
   // Plug in test content browser client.
   SelectCertificateBrowserClient test_client;
@@ skipping 14 matching lines @@
   // Check if the retrieved certificates were passed to the content browser
   // client.
   EXPECT_EQ(1, test_client.call_count());
   EXPECT_EQ(dummy_certs, test_client.passed_certs());
 }
 
 // Verifies if a call to net::URLRequest::Delegate::OnCertificateRequested()
 // on a platform with a NULL client cert store still calls the content browser
 // client for selection.
 TEST_F(ResourceLoaderTest, ClientCertStoreNull) {
-  const int kRenderProcessId = 1;
-  const int kRenderViewId = 2;
-
-  scoped_ptr<net::URLRequest> request(
-      new net::URLRequest(GURL("dummy"),
-                          net::DEFAULT_PRIORITY,
-                          NULL,
-                          resource_context_.GetRequestContext()));
-  ResourceRequestInfo::AllocateForTesting(request.get(),
-                                          ResourceType::MAIN_FRAME,
-                                          &resource_context_,
-                                          kRenderProcessId,
-                                          kRenderViewId,
-                                          MSG_ROUTING_NONE,
-                                          false);
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(GURL("dummy"));
 
   // Ownership of the |request| is about to be turned over to ResourceLoader. We
   // need to keep a raw pointer copy to access this object later.
   net::URLRequest* raw_ptr_to_request = request.get();
 
-  scoped_ptr<ResourceHandler> resource_handler(new ResourceHandlerStub());
+  scoped_ptr<ResourceHandler> resource_handler(
+      new ResourceHandlerStub(request.get()));
   ResourceLoader loader(request.Pass(), resource_handler.Pass(), this);
 
   // Prepare a dummy certificate request.
   scoped_refptr<net::SSLCertRequestInfo> cert_request_info(
       new net::SSLCertRequestInfo());
   std::vector<std::string> dummy_authority(1, "dummy");
   cert_request_info->cert_authorities = dummy_authority;
 
   // Plug in test content browser client.
   SelectCertificateBrowserClient test_client;
   ContentBrowserClient* old_client = SetBrowserClientForTesting(&test_client);
 
   // Everything is set up. Trigger the resource loader certificate request event
   // and run the message loop.
   loader.OnCertificateRequested(raw_ptr_to_request, cert_request_info.get());
   base::RunLoop().RunUntilIdle();
 
   // Restore the original content browser client.
   SetBrowserClientForTesting(old_client);
 
   // Check if the SelectClientCertificate was called on the content browser
   // client.
   EXPECT_EQ(1, test_client.call_count());
   EXPECT_EQ(net::CertificateList(), test_client.passed_certs());
 }
 
+// Tests that a RedirectToFileResourceHandler works and forwards everything
+// downstream.
+TEST_F(ResourceLoaderTest, RedirectToFile) {
+  MockTemporaryFileStream temporary_file_stream;
+  base::FilePath temp_path = temporary_file_stream.deletable_file()->path();
+
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      temporary_file_stream.Callback()));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Run it to completion.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // Check that the handler forwarded all information to the downstream handler.
+  EXPECT_EQ(temp_path, leaf_handler->response()->head.download_file_path);
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::SUCCESS, leaf_handler->status().status());
+  EXPECT_EQ(net::URLRequestTestJob::test_data_1().size(),
+            static_cast<size_t>(leaf_handler->total_bytes_downloaded()));
+
+  // Check that the data was written to the file.
+  std::string contents;
+  ASSERT_TRUE(base::ReadFileToString(temp_path, &contents));
+  EXPECT_EQ(net::URLRequestTestJob::test_data_1(), contents);
+
+  // Release the loader. The file should be gone now.
+  loader.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(base::PathExists(temp_path));
+}
+
+// Tests that RedirectToFileResourceHandler handles errors in creating the
+// temporary file.
+TEST_F(ResourceLoaderTest, RedirectToFileCreateTemporaryError) {
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      base::Bind(&CreateTemporaryError, base::PLATFORM_FILE_ERROR_FAILED)));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Run it to completion.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // To downstream, the request was canceled.
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::CANCELED, leaf_handler->status().status());
+  EXPECT_EQ(0, leaf_handler->total_bytes_downloaded());
+}
+
+// Tests that RedirectToFileResourceHandler handles synchronous write errors.
+TEST_F(ResourceLoaderTest, RedirectToFileWriteError) {
+  MockTemporaryFileStream temporary_file_stream;
+  base::FilePath temp_path = temporary_file_stream.deletable_file()->path();
+  net::testing::MockFileStream* mock_file_stream =
+      temporary_file_stream.file_stream();
+  mock_file_stream->set_forced_error(net::ERR_FAILED);
+
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      temporary_file_stream.Callback()));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Run it to completion.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // To downstream, the request was canceled sometime after it started, but
+  // before any data was written.
+  EXPECT_EQ(temp_path, leaf_handler->response()->head.download_file_path);
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::CANCELED, leaf_handler->status().status());
+  EXPECT_EQ(0, leaf_handler->total_bytes_downloaded());
+}
+
+// Tests that RedirectToFileResourceHandler handles asynchronous write errors.
+TEST_F(ResourceLoaderTest, RedirectToFileWriteErrorAsync) {
+  MockTemporaryFileStream temporary_file_stream;
+  base::FilePath temp_path = temporary_file_stream.deletable_file()->path();
+  net::testing::MockFileStream* mock_file_stream =
+      temporary_file_stream.file_stream();
+  mock_file_stream->set_forced_error_async(net::ERR_FAILED);
+
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      temporary_file_stream.Callback()));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Run it to completion.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // To downstream, the request was canceled sometime after it started, but
+  // before any data was written.
+  EXPECT_EQ(temp_path, leaf_handler->response()->head.download_file_path);
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::CANCELED, leaf_handler->status().status());
+  EXPECT_EQ(0, leaf_handler->total_bytes_downloaded());
+}
+
+// Tests that RedirectToFileHandler defers completion if there are outstanding
+// writes and accounts for errors which occur in that time.
+TEST_F(ResourceLoaderTest, RedirectToFileDeferCompletion) {
+  // Program the MockFileStream to error asynchronously, but throttle the
+  // callback.
+  MockTemporaryFileStream temporary_file_stream;
+  base::FilePath temp_path = temporary_file_stream.deletable_file()->path();
+  net::testing::MockFileStream* mock_file_stream =
+      temporary_file_stream.file_stream();
+  mock_file_stream->set_forced_error_async(net::ERR_FAILED);
+  mock_file_stream->ThrottleCallbacks();
+
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  net::URLRequest* raw_ptr_to_request = request.get();
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      temporary_file_stream.Callback()));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Run it as far as it will go.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // At this point, the request should have completed.
+  EXPECT_EQ(net::URLRequestStatus::SUCCESS,
+            raw_ptr_to_request->status().status());
+
+  // However, the resource loader stack is stuck somewhere after receiving the
+  // response.
+  EXPECT_EQ(temp_path, leaf_handler->response()->head.download_file_path);
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_FALSE(leaf_handler->received_response_completed());
+  EXPECT_EQ(0, leaf_handler->total_bytes_downloaded());
+
+  // Now, release the floodgates.
+  mock_file_stream->ReleaseCallbacks();
+  base::RunLoop().RunUntilIdle();
+
+  // Although the URLRequest was successful, the leaf handler sees a failure
+  // because the write never completed.
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::CANCELED, leaf_handler->status().status());
+}
+
+// Tests that a RedirectToFileResourceHandler behaves properly when the
+// downstream handler defers OnWillStart.
+TEST_F(ResourceLoaderTest, RedirectToFileDownstreamDeferStart) {
+  MockTemporaryFileStream temporary_file_stream;
+  base::FilePath temp_path =
+      temporary_file_stream.deletable_file()->path();
+
+  // Set up the request.
+  scoped_ptr<net::URLRequest> request = CreateTestRequest(
+      net::URLRequestTestJob::test_url_1());
+  ResourceHandlerStub* leaf_handler = new ResourceHandlerStub(request.get());
+  scoped_ptr<ResourceHandler> resource_handler(leaf_handler);
+  resource_handler.reset(new RedirectToFileResourceHandler(
+      resource_handler.Pass(), request.get(),
+      temporary_file_stream.Callback()));
+  scoped_ptr<ResourceLoader> loader(new ResourceLoader(
+      request.Pass(), resource_handler.Pass(), this));
+
+  // Defer OnWillStart.
+  leaf_handler->set_defer_start(true);
+
+  // Run as far as we'll go.
+  loader->StartRequest();
+  base::RunLoop().RunUntilIdle();
+
+  // The request should have stopped at OnWillStart.
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_FALSE(leaf_handler->response());
+  EXPECT_FALSE(leaf_handler->received_response_completed());
+  EXPECT_EQ(0, leaf_handler->total_bytes_downloaded());
+
+  // Now resume the request. Now we complete.
+  leaf_handler->Resume();
+  base::RunLoop().RunUntilIdle();
+
+  // Check that the handler forwarded all information to the downstream handler.
+  EXPECT_EQ(temp_path, leaf_handler->response()->head.download_file_path);
+  EXPECT_EQ(net::URLRequestTestJob::test_url_1(), leaf_handler->start_url());
+  EXPECT_TRUE(leaf_handler->received_response_completed());
+  EXPECT_EQ(net::URLRequestStatus::SUCCESS, leaf_handler->status().status());
+  EXPECT_EQ(net::URLRequestTestJob::test_data_1().size(),
+            static_cast<size_t>(leaf_handler->total_bytes_downloaded()));
+
+  // Check that the data was written to the file.
+  std::string contents;
+  ASSERT_TRUE(base::ReadFileToString(temp_path, &contents));
+  EXPECT_EQ(net::URLRequestTestJob::test_data_1(), contents);
+
+  // Release the loader. The file should be gone now.
+  loader.reset();
+  base::RunLoop().RunUntilIdle();
+  EXPECT_FALSE(base::PathExists(temp_path));
+}
+
 }  // namespace content