Fix network service hanging with empty bodies.

content/network/url_loader_unittest.cc

 // Copyright 2017 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/files/file_util.h"
 #include "base/message_loop/message_loop.h"
 #include "base/path_service.h"
 #include "base/run_loop.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "content/browser/loader/test_url_loader_client.h"
@@ skipping 26 matching lines @@
   request.download_to_file = false;
   request.should_reset_appcache = false;
   request.is_main_frame = true;
   request.parent_is_main_frame = false;
   request.transition_type = ui::PAGE_TRANSITION_LINK;
   request.allow_download = true;
   return request;
 }
 
 std::string ReadData(MojoHandle consumer, size_t size) {
-  CHECK_EQ(mojo::Wait(mojo::Handle(consumer), MOJO_HANDLE_SIGNAL_READABLE),
-           MOJO_RESULT_OK);
+  MojoResult rv =
+      mojo::Wait(mojo::Handle(consumer), MOJO_HANDLE_SIGNAL_READABLE);
+  if (!size) {
+    CHECK_EQ(rv, MOJO_RESULT_FAILED_PRECONDITION);
+    return std::string();
+  }
+  CHECK_EQ(rv, MOJO_RESULT_OK);
   std::vector<char> buffer(size);
   uint32_t num_bytes = static_cast<uint32_t>(size);
   CHECK_EQ(MojoReadData(consumer, buffer.data(), &num_bytes,
                         MOJO_WRITE_DATA_FLAG_ALL_OR_NONE),
            MOJO_RESULT_OK);
   CHECK_EQ(num_bytes, static_cast<uint32_t>(size));
 
   return std::string(buffer.data(), buffer.size());
 }
 
@@ skipping 50 matching lines @@
  private:
   base::MessageLoopForIO message_loop_;
   net::EmbeddedTestServer test_server_;
   std::unique_ptr<NetworkContext> context_;
 };
 
 TEST_F(URLLoaderImplTest, Basic) {
   LoadAndCompareFile("simple_page.html");
 }
 
+TEST_F(URLLoaderImplTest, Empty) {
+  LoadAndCompareFile("empty.html");
+}
+
 TEST_F(URLLoaderImplTest, BasicSSL) {
   net::EmbeddedTestServer https_server(net::EmbeddedTestServer::TYPE_HTTPS);
   https_server.ServeFilesFromSourceDirectory(
       base::FilePath(FILE_PATH_LITERAL("content/test/data")));
   ASSERT_TRUE(https_server.Start());
 
   TestURLLoaderClient client;
   GURL url = https_server.GetURL("/simple_page.html");
   Load(url, &client, mojom::kURLLoadOptionSendSSLInfo);
   ASSERT_TRUE(!!client.ssl_info());
   ASSERT_TRUE(!!client.ssl_info()->cert);
 
   ASSERT_TRUE(
       https_server.GetCertificate()->Equals(client.ssl_info()->cert.get()));
 }
 
 TEST_F(URLLoaderImplTest, SSLSentOnlyWhenRequested) {
   net::EmbeddedTestServer https_server(net::EmbeddedTestServer::TYPE_HTTPS);
   https_server.ServeFilesFromSourceDirectory(
       base::FilePath(FILE_PATH_LITERAL("content/test/data")));
   ASSERT_TRUE(https_server.Start());
 
   TestURLLoaderClient client;
   GURL url = https_server.GetURL("/simple_page.html");
   Load(url, &client, 0);
   ASSERT_FALSE(!!client.ssl_info());
 }
 
 }  // namespace content