Avoid log spam in AudioSyncReader.

content/browser/renderer_host/media/audio_input_sync_writer.cc

Index: content/browser/renderer_host/media/audio_input_sync_writer.cc
diff --git a/content/browser/renderer_host/media/audio_input_sync_writer.cc b/content/browser/renderer_host/media/audio_input_sync_writer.cc
index c72b1cd7b0e5b1be50ccc754bcb6fc4d1b5dd336..de719c3bcabfc08184de86c6e4a6fd9ff41851bc 100644
--- a/content/browser/renderer_host/media/audio_input_sync_writer.cc
+++ b/content/browser/renderer_host/media/audio_input_sync_writer.cc
@@ -5,6 +5,7 @@
 #include "content/browser/renderer_host/media/audio_input_sync_writer.h"
 
 #include <algorithm>
+#include <utility>
 
 #include "base/format_macros.h"
 #include "base/metrics/histogram_macros.h"
@@ -47,6 +48,7 @@ AudioInputSyncWriter::AudioInputSyncWriter(void* shared_memory,
       write_count_(0),
       write_to_fifo_count_(0),
       write_error_count_(0),
+      had_socket_error_(false),
       trailing_write_to_fifo_count_(0),
       trailing_write_error_count_(0) {
   DCHECK_GT(shared_memory_segment_count, 0);
@@ -327,9 +329,11 @@ void AudioInputSyncWriter::WriteParametersToCurrentSegment(
 
 bool AudioInputSyncWriter::SignalDataWrittenAndUpdateCounters() {
   if (socket_->Send(&current_segment_id_, sizeof(current_segment_id_)) !=
-      sizeof(current_segment_id_)) {
+          sizeof(current_segment_id_) &&
+      !had_socket_error_) {
+    had_socket_error_ = true;

[tommi (sloooow) - chröme, 2017/04/18 09:39:28]

Can we ever recover from this?
If not, can we have a DCHECK below?
If we can, where should the flag be cleared?

[Max Morin, 2017/04/18 09:55:28]

In the case in the bug (other end of sync socket is closed) we cannot recover,
but it's an ok state for the program to be in (while closing the stream).
Looking at http://man7.org/linux/man-pages/man2/write.2.html, I think ENOSPC is
an error we could recover from. Do you think we should clear the flag if Send
succeeds?

[tommi (sloooow) - chröme, 2017/04/19 10:44:35]

Yes I think that would be a safer change to make at this point. We'll still
reduce the spam but if we recover, errors that might occur at a later stage,
will be reported.

[Max Morin, 2017/04/19 11:51:00]

Makes sense. I changed it.

     const std::string error_message = "AISW: No room in socket buffer.";
-    LOG(WARNING) << error_message;
+    PLOG(WARNING) << error_message;
     AddToNativeLog(error_message);
     TRACE_EVENT_INSTANT0("audio",
                          "AudioInputSyncWriter: No room in socket buffer",