Refactor AppendToFile and WriteFileDescriptor

content/common/gpu/media/video_encode_accelerator_unittest.cc

 // Copyright 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 "base/at_exit.h"
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
 #include "base/files/memory_mapped_file.h"
 #include "base/memory/scoped_vector.h"
@@ skipping 807 matching lines @@
 
   const uint8* stream_ptr = static_cast<const uint8*>(shm->memory());
   if (payload_size > 0)
     validator_->ProcessStreamBuffer(stream_ptr, payload_size);
 
   EXPECT_EQ(key_frame, seen_keyframe_in_this_buffer_);
   seen_keyframe_in_this_buffer_ = false;
 
   if (save_to_file_) {
     int size = base::checked_cast<int>(payload_size);
-    EXPECT_EQ(base::AppendToFile(
-                  base::FilePath::FromUTF8Unsafe(test_stream_->out_filename),
-                  static_cast<char*>(shm->memory()),
-                  size),
-              size);
+    EXPECT_TRUE(base::AppendToFile(
+                    base::FilePath::FromUTF8Unsafe(test_stream_->out_filename),
+                    static_cast<char*>(shm->memory()),
+                    size));
   }
 
   FeedEncoderWithOutput(shm);
 }
 
 void VEAClient::NotifyError(VideoEncodeAccelerator::Error error) {
   DCHECK(thread_checker_.CalledOnValidThread());
   SetState(CS_ERROR);
 }
 
@@ skipping 361 matching lines @@
   }
 
   content::g_env =
       reinterpret_cast<content::VideoEncodeAcceleratorTestEnvironment*>(
           testing::AddGlobalTestEnvironment(
               new content::VideoEncodeAcceleratorTestEnvironment(
                   test_stream_data.Pass())));
 
   return RUN_ALL_TESTS();
 }