Eliminate usage of InterfacePtr::WaitForIncomingResponse.

components/filesystem/file_impl_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 <stddef.h>
 #include <stdint.h>
 #include <utility>
 #include <vector>
 
 #include "base/files/file.h"
 #include "components/filesystem/files_test_base.h"
 #include "mojo/public/cpp/bindings/interface_request.h"
 #include "mojo/public/cpp/bindings/type_converter.h"
 #include "mojo/public/cpp/system/platform_handle.h"
 
 namespace filesystem {
 namespace {
 
 using FileImplTest = FilesTestBase;
 
 TEST_F(FileImplTest, CreateWriteCloseRenameOpenRead) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
+  bool handled = false;
 
   {
     // Create my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagWrite | mojom::kFlagCreate,
-                        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagWrite | mojom::kFlagCreate, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     std::vector<uint8_t> bytes_to_write;
     bytes_to_write.push_back(static_cast<uint8_t>('h'));
     bytes_to_write.push_back(static_cast<uint8_t>('e'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close((&error));
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   // Rename it.
   error = mojom::FileError::FAILED;
-  directory->Rename("my_file", "your_file", Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  handled = directory->Rename("my_file", "your_file", &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   {
     // Open my_file again.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("your_file", GetProxy(&file),
-                        mojom::kFlagRead | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("your_file", GetProxy(&file),
+                            mojom::kFlagRead | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Read from it.
     mojo::Array<uint8_t> bytes_read;
     error = mojom::FileError::FAILED;
-    file->Read(3, 1, mojom::Whence::FROM_BEGIN, Capture(&error, &bytes_read));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Read(3, 1, mojom::Whence::FROM_BEGIN, &error, &bytes_read);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     ASSERT_EQ(3u, bytes_read.size());
     EXPECT_EQ(static_cast<uint8_t>('e'), bytes_read[0]);
     EXPECT_EQ(static_cast<uint8_t>('l'), bytes_read[1]);
     EXPECT_EQ(static_cast<uint8_t>('l'), bytes_read[2]);
   }
 
   // TODO(vtl): Test read/write offset options.
 }
 
 TEST_F(FileImplTest, CantWriteInReadMode) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   std::vector<uint8_t> bytes_to_write;
   bytes_to_write.push_back(static_cast<uint8_t>('h'));
   bytes_to_write.push_back(static_cast<uint8_t>('e'));
   bytes_to_write.push_back(static_cast<uint8_t>('l'));
   bytes_to_write.push_back(static_cast<uint8_t>('l'));
   bytes_to_write.push_back(static_cast<uint8_t>('o'));
 
   {
     // Create my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagWrite | mojom::kFlagCreate,
-                        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagWrite | mojom::kFlagCreate, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close((&error));
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Open my_file again, this time with read only mode.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagRead | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagRead | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Try to write in read mode; it should fail.
     error = mojom::FileError::OK;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
 
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::FAILED, error);
     EXPECT_EQ(0u, num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close((&error));
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 }
 
 TEST_F(FileImplTest, OpenInAppendMode) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   {
     // Create my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagWrite | mojom::kFlagCreate,
-                        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagWrite | mojom::kFlagCreate, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     std::vector<uint8_t> bytes_to_write;
     bytes_to_write.push_back(static_cast<uint8_t>('h'));
     bytes_to_write.push_back(static_cast<uint8_t>('e'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close(&error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Append to my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagAppend | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagAppend | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     std::vector<uint8_t> bytes_to_write;
     bytes_to_write.push_back(static_cast<uint8_t>('g'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     bytes_to_write.push_back(static_cast<uint8_t>('d'));
     bytes_to_write.push_back(static_cast<uint8_t>('b'));
     bytes_to_write.push_back(static_cast<uint8_t>('y'));
     bytes_to_write.push_back(static_cast<uint8_t>('e'));
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close((&error));
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Open my_file again.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagRead | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagRead | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Read from it.
     mojo::Array<uint8_t> bytes_read;
     error = mojom::FileError::FAILED;
-    file->Read(12, 0, mojom::Whence::FROM_BEGIN, Capture(&error, &bytes_read));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Read(12, 0, mojom::Whence::FROM_BEGIN, &error, &bytes_read);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     ASSERT_EQ(12u, bytes_read.size());
     EXPECT_EQ(static_cast<uint8_t>('l'), bytes_read[3]);
     EXPECT_EQ(static_cast<uint8_t>('o'), bytes_read[4]);
     EXPECT_EQ(static_cast<uint8_t>('g'), bytes_read[5]);
     EXPECT_EQ(static_cast<uint8_t>('o'), bytes_read[6]);
   }
 }
 
 TEST_F(FileImplTest, OpenInTruncateMode) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   {
     // Create my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagWrite | mojom::kFlagCreate,
-                        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagWrite | mojom::kFlagCreate, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     std::vector<uint8_t> bytes_to_write;
     bytes_to_write.push_back(static_cast<uint8_t>('h'));
     bytes_to_write.push_back(static_cast<uint8_t>('e'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('l'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close(&error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Append to my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagWrite | mojom::kFlagOpenTruncated,
-                        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled = directory->OpenFile(
+        "my_file", GetProxy(&file),
+        mojom::kFlagWrite | mojom::kFlagOpenTruncated, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Write to it.
     std::vector<uint8_t> bytes_to_write;
     bytes_to_write.push_back(static_cast<uint8_t>('g'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     bytes_to_write.push_back(static_cast<uint8_t>('o'));
     bytes_to_write.push_back(static_cast<uint8_t>('d'));
     bytes_to_write.push_back(static_cast<uint8_t>('b'));
     bytes_to_write.push_back(static_cast<uint8_t>('y'));
     bytes_to_write.push_back(static_cast<uint8_t>('e'));
     error = mojom::FileError::FAILED;
     uint32_t num_bytes_written = 0;
-    file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-                mojom::Whence::FROM_CURRENT,
-                Capture(&error, &num_bytes_written));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled =
+        file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                    mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
 
     // Close it.
     error = mojom::FileError::FAILED;
-    file->Close(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Close(&error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Open my_file again.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file),
-                        mojom::kFlagRead | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file),
+                            mojom::kFlagRead | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Read from it.
     mojo::Array<uint8_t> bytes_read;
     error = mojom::FileError::FAILED;
-    file->Read(7, 0, mojom::Whence::FROM_BEGIN, Capture(&error, &bytes_read));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Read(7, 0, mojom::Whence::FROM_BEGIN, &error, &bytes_read);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     ASSERT_EQ(7u, bytes_read.size());
     EXPECT_EQ(static_cast<uint8_t>('g'), bytes_read[0]);
     EXPECT_EQ(static_cast<uint8_t>('o'), bytes_read[1]);
     EXPECT_EQ(static_cast<uint8_t>('o'), bytes_read[2]);
     EXPECT_EQ(static_cast<uint8_t>('d'), bytes_read[3]);
   }
 }
 
 // Note: Ignore nanoseconds, since it may not always be supported. We expect at
 // least second-resolution support though.
 TEST_F(FileImplTest, StatTouch) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file),
-                      mojom::kFlagWrite | mojom::kFlagCreate, Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled =
+      directory->OpenFile("my_file", GetProxy(&file),
+                          mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Stat it.
   error = mojom::FileError::FAILED;
   mojom::FileInformationPtr file_info;
-  file->Stat(Capture(&error, &file_info));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Stat(&error, &file_info);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_FALSE(file_info.is_null());
   EXPECT_EQ(mojom::FsFileType::REGULAR_FILE, file_info->type);
   EXPECT_EQ(0, file_info->size);
   EXPECT_GT(file_info->atime, 0);  // Expect that it's not 1970-01-01.
   EXPECT_GT(file_info->mtime, 0);
   double first_mtime = file_info->mtime;
 
   // Touch only the atime.
   error = mojom::FileError::FAILED;
   mojom::TimespecOrNowPtr t(mojom::TimespecOrNow::New());
   t->now = false;
   const int64_t kPartyTime1 = 1234567890;  // Party like it's 2009-02-13.
   t->seconds = kPartyTime1;
-  file->Touch(std::move(t), nullptr, Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Touch(std::move(t), nullptr, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Stat again.
   error = mojom::FileError::FAILED;
   file_info.reset();
-  file->Stat(Capture(&error, &file_info));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Stat(&error, &file_info);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_FALSE(file_info.is_null());
   EXPECT_EQ(kPartyTime1, file_info->atime);
   EXPECT_EQ(first_mtime, file_info->mtime);
 
   // Touch only the mtime.
   t = mojom::TimespecOrNow::New();
   t->now = false;
   const int64_t kPartyTime2 = 1425059525;  // No time like the present.
   t->seconds = kPartyTime2;
-  file->Touch(nullptr, std::move(t), Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Touch(nullptr, std::move(t), &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Stat again.
   error = mojom::FileError::FAILED;
   file_info.reset();
-  file->Stat(Capture(&error, &file_info));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Stat(&error, &file_info);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_FALSE(file_info.is_null());
   EXPECT_EQ(kPartyTime1, file_info->atime);
   EXPECT_EQ(kPartyTime2, file_info->mtime);
 
   // TODO(vtl): Also test non-zero file size.
   // TODO(vtl): Also test Touch() "now" options.
   // TODO(vtl): Also test touching both atime and mtime.
 }
 
 TEST_F(FileImplTest, TellSeek) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file),
-                      mojom::kFlagWrite | mojom::kFlagCreate, Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled =
+      directory->OpenFile("my_file", GetProxy(&file),
+                          mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Write to it.
   std::vector<uint8_t> bytes_to_write(1000, '!');
   error = mojom::FileError::FAILED;
   uint32_t num_bytes_written = 0;
-  file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-              mojom::Whence::FROM_CURRENT, Capture(&error, &num_bytes_written));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled =
+      file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                  mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
   const int size = static_cast<int>(num_bytes_written);
 
   // Tell.
   error = mojom::FileError::FAILED;
   int64_t position = -1;
-  file->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   // Should be at the end.
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(size, position);
 
   // Seek back 100.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Seek(-100, mojom::Whence::FROM_CURRENT, Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Seek(-100, mojom::Whence::FROM_CURRENT, &error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(size - 100, position);
 
   // Tell.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(size - 100, position);
 
   // Seek to 123 from start.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Seek(123, mojom::Whence::FROM_BEGIN, Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Seek(123, mojom::Whence::FROM_BEGIN, &error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(123, position);
 
   // Tell.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(123, position);
 
   // Seek to 123 back from end.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Seek(-123, mojom::Whence::FROM_END, Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Seek(-123, mojom::Whence::FROM_END, &error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(size - 123, position);
 
   // Tell.
   error = mojom::FileError::FAILED;
   position = -1;
-  file->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(size - 123, position);
 
   // TODO(vtl): Check that seeking actually affects reading/writing.
   // TODO(vtl): Check that seeking can extend the file?
 }
 
 TEST_F(FileImplTest, Dup) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file1;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file1),
-                      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate,
-                      Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled = directory->OpenFile(
+      "my_file", GetProxy(&file1),
+      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Write to it.
   std::vector<uint8_t> bytes_to_write;
   bytes_to_write.push_back(static_cast<uint8_t>('h'));
   bytes_to_write.push_back(static_cast<uint8_t>('e'));
   bytes_to_write.push_back(static_cast<uint8_t>('l'));
   bytes_to_write.push_back(static_cast<uint8_t>('l'));
   bytes_to_write.push_back(static_cast<uint8_t>('o'));
   error = mojom::FileError::FAILED;
   uint32_t num_bytes_written = 0;
-  file1->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-               mojom::Whence::FROM_CURRENT,
-               Capture(&error, &num_bytes_written));
-  ASSERT_TRUE(file1.WaitForIncomingResponse());
+  handled =
+      file1->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                   mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(bytes_to_write.size(), num_bytes_written);
   const int end_hello_pos = static_cast<int>(num_bytes_written);
 
   // Dup it.
   mojom::FilePtr file2;
   error = mojom::FileError::FAILED;
-  file1->Dup(GetProxy(&file2), Capture(&error));
-  ASSERT_TRUE(file1.WaitForIncomingResponse());
+  handled = file1->Dup(GetProxy(&file2), &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // |file2| should have the same position.
   error = mojom::FileError::FAILED;
   int64_t position = -1;
-  file2->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file2.WaitForIncomingResponse());
+  handled = file2->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(end_hello_pos, position);
 
   // Write using |file2|.
   std::vector<uint8_t> more_bytes_to_write;
   more_bytes_to_write.push_back(static_cast<uint8_t>('w'));
   more_bytes_to_write.push_back(static_cast<uint8_t>('o'));
   more_bytes_to_write.push_back(static_cast<uint8_t>('r'));
   more_bytes_to_write.push_back(static_cast<uint8_t>('l'));
   more_bytes_to_write.push_back(static_cast<uint8_t>('d'));
   error = mojom::FileError::FAILED;
   num_bytes_written = 0;
-  file2->Write(mojo::Array<uint8_t>::From(more_bytes_to_write), 0,
-               mojom::Whence::FROM_CURRENT,
-               Capture(&error, &num_bytes_written));
-  ASSERT_TRUE(file2.WaitForIncomingResponse());
+  handled =
+      file2->Write(mojo::Array<uint8_t>::From(more_bytes_to_write), 0,
+                   mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(more_bytes_to_write.size(), num_bytes_written);
   const int end_world_pos = end_hello_pos + static_cast<int>(num_bytes_written);
 
   // |file1| should have the same position.
   error = mojom::FileError::FAILED;
   position = -1;
-  file1->Tell(Capture(&error, &position));
-  ASSERT_TRUE(file1.WaitForIncomingResponse());
+  handled = file1->Tell(&error, &position);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(end_world_pos, position);
 
   // Close |file1|.
   error = mojom::FileError::FAILED;
-  file1->Close(Capture(&error));
-  ASSERT_TRUE(file1.WaitForIncomingResponse());
+  handled = file1->Close(&error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Read everything using |file2|.
   mojo::Array<uint8_t> bytes_read;
   error = mojom::FileError::FAILED;
-  file2->Read(1000, 0, mojom::Whence::FROM_BEGIN, Capture(&error, &bytes_read));
-  ASSERT_TRUE(file2.WaitForIncomingResponse());
+  handled =
+      file2->Read(1000, 0, mojom::Whence::FROM_BEGIN, &error, &bytes_read);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_EQ(static_cast<size_t>(end_world_pos), bytes_read.size());
   // Just check the first and last bytes.
   EXPECT_EQ(static_cast<uint8_t>('h'), bytes_read[0]);
   EXPECT_EQ(static_cast<uint8_t>('d'), bytes_read[end_world_pos - 1]);
 
   // TODO(vtl): Test that |file2| has the same open options as |file1|.
 }
 
 TEST_F(FileImplTest, Truncate) {
   const uint32_t kInitialSize = 1000;
   const uint32_t kTruncatedSize = 654;
 
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file),
-                      mojom::kFlagWrite | mojom::kFlagCreate, Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled =
+      directory->OpenFile("my_file", GetProxy(&file),
+                          mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Write to it.
   std::vector<uint8_t> bytes_to_write(kInitialSize, '!');
   error = mojom::FileError::FAILED;
   uint32_t num_bytes_written = 0;
-  file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
-              mojom::Whence::FROM_CURRENT, Capture(&error, &num_bytes_written));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled =
+      file->Write(mojo::Array<uint8_t>::From(bytes_to_write), 0,
+                  mojom::Whence::FROM_CURRENT, &error, &num_bytes_written);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   EXPECT_EQ(kInitialSize, num_bytes_written);
 
   // Stat it.
   error = mojom::FileError::FAILED;
   mojom::FileInformationPtr file_info;
-  file->Stat(Capture(&error, &file_info));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Stat(&error, &file_info);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_FALSE(file_info.is_null());
   EXPECT_EQ(kInitialSize, file_info->size);
 
   // Truncate it.
   error = mojom::FileError::FAILED;
-  file->Truncate(kTruncatedSize, Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Truncate(kTruncatedSize, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Stat again.
   error = mojom::FileError::FAILED;
   file_info.reset();
-  file->Stat(Capture(&error, &file_info));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Stat(&error, &file_info);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
   ASSERT_FALSE(file_info.is_null());
   EXPECT_EQ(kTruncatedSize, file_info->size);
 }
 
 TEST_F(FileImplTest, AsHandle) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   {
     // Create my_file.
     mojom::FilePtr file1;
     error = mojom::FileError::FAILED;
-    directory->OpenFile(
+    bool handled = directory->OpenFile(
         "my_file", GetProxy(&file1),
-        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate,
-        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Fetch the handle
     error = mojom::FileError::FAILED;
     mojo::ScopedHandle handle;
-    file1->AsHandle(Capture(&error, &handle));
-    ASSERT_TRUE(file1.WaitForIncomingResponse());
+    handled = file1->AsHandle(&error, &handle);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Pull a file descriptor out of the scoped handle.
     base::PlatformFile platform_file;
     MojoResult unwrap_result = mojo::UnwrapPlatformFile(std::move(handle),
                                                         &platform_file);
     EXPECT_EQ(MOJO_RESULT_OK, unwrap_result);
 
     // Pass this raw file descriptor to a base::File.
     base::File raw_file(platform_file);
     ASSERT_TRUE(raw_file.IsValid());
     EXPECT_EQ(5, raw_file.WriteAtCurrentPos("hello", 5));
   }
 
   {
     // Reopen my_file.
     mojom::FilePtr file2;
     error = mojom::FileError::FAILED;
-    directory->OpenFile("my_file", GetProxy(&file2),
-                        mojom::kFlagRead | mojom::kFlagOpen, Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+    bool handled =
+        directory->OpenFile("my_file", GetProxy(&file2),
+                            mojom::kFlagRead | mojom::kFlagOpen, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Verify that we wrote data raw on the file descriptor.
     mojo::Array<uint8_t> bytes_read;
     error = mojom::FileError::FAILED;
-    file2->Read(5, 0, mojom::Whence::FROM_BEGIN, Capture(&error, &bytes_read));
-    ASSERT_TRUE(file2.WaitForIncomingResponse());
+    handled = file2->Read(5, 0, mojom::Whence::FROM_BEGIN, &error, &bytes_read);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
     ASSERT_EQ(5u, bytes_read.size());
     EXPECT_EQ(static_cast<uint8_t>('h'), bytes_read[0]);
     EXPECT_EQ(static_cast<uint8_t>('e'), bytes_read[1]);
     EXPECT_EQ(static_cast<uint8_t>('l'), bytes_read[2]);
     EXPECT_EQ(static_cast<uint8_t>('l'), bytes_read[3]);
     EXPECT_EQ(static_cast<uint8_t>('o'), bytes_read[4]);
   }
 }
 
 TEST_F(FileImplTest, SimpleLockUnlock) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file),
-                      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate,
-                      Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled = directory->OpenFile(
+      "my_file", GetProxy(&file),
+      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Lock the file.
   error = mojom::FileError::FAILED;
-  file->Lock(Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Lock(&error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Unlock the file.
   error = mojom::FileError::FAILED;
-  file->Unlock(Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Unlock(&error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 }
 
 TEST_F(FileImplTest, CantDoubleLock) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   // Create my_file.
   mojom::FilePtr file;
   error = mojom::FileError::FAILED;
-  directory->OpenFile("my_file", GetProxy(&file),
-                      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate,
-                      Capture(&error));
-  ASSERT_TRUE(directory.WaitForIncomingResponse());
+  bool handled = directory->OpenFile(
+      "my_file", GetProxy(&file),
+      mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagCreate, &error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Lock the file.
   error = mojom::FileError::FAILED;
-  file->Lock(Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Lock(&error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::OK, error);
 
   // Lock the file again.
   error = mojom::FileError::OK;
-  file->Lock(Capture(&error));
-  ASSERT_TRUE(file.WaitForIncomingResponse());
+  handled = file->Lock(&error);
+  ASSERT_TRUE(handled);
   EXPECT_EQ(mojom::FileError::FAILED, error);
 }
 
 TEST_F(FileImplTest, ClosingFileClearsLock) {
   mojom::DirectoryPtr directory;
   GetTemporaryRoot(&directory);
   mojom::FileError error;
 
   {
     // Create my_file.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile(
+    bool handled = directory->OpenFile(
         "my_file", GetProxy(&file),
-        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagOpenAlways,
-        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagOpenAlways, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // Lock the file.
     error = mojom::FileError::FAILED;
-    file->Lock(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Lock(&error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 
   {
     // Open the file again.
     mojom::FilePtr file;
     error = mojom::FileError::FAILED;
-    directory->OpenFile(
+    bool handled = directory->OpenFile(
         "my_file", GetProxy(&file),
-        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagOpenAlways,
-        Capture(&error));
-    ASSERT_TRUE(directory.WaitForIncomingResponse());
+        mojom::kFlagRead | mojom::kFlagWrite | mojom::kFlagOpenAlways, &error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
 
     // The file shouldn't be locked (and we check by trying to lock it).
     error = mojom::FileError::FAILED;
-    file->Lock(Capture(&error));
-    ASSERT_TRUE(file.WaitForIncomingResponse());
+    handled = file->Lock(&error);
+    ASSERT_TRUE(handled);
     EXPECT_EQ(mojom::FileError::OK, error);
   }
 }
 
 }  // namespace
 }  // namespace filesystem