Remove AudioBuffersState usage in Chromium

media/audio/audio_device_thread.cc

 // Copyright (c) 2012 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 "media/audio/audio_device_thread.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/memory/aligned_memory.h"
 #include "base/message_loop/message_loop.h"
+#include "base/numerics/safe_conversions.h"
 #include "base/threading/platform_thread.h"
 #include "base/threading/thread_restrictions.h"
 #include "media/base/audio_bus.h"
 
 using base::PlatformThread;
 
 namespace media {
 
 // The actual worker thread implementation.  It's very bare bones and much
 // simpler than SimpleThread (no synchronization in Start, etc) and supports
@@ skipping 134 matching lines @@
   Run();
 
   // Release the reference for the thread. Note that after this, the Thread
   // instance will most likely be deleted.
   Release();
 }
 
 void AudioDeviceThread::Thread::Run() {
   uint32 buffer_index = 0;
   while (true) {
-    int pending_data = 0;
+    uint32 pending_data = 0;
     size_t bytes_read = socket_.Receive(&pending_data, sizeof(pending_data));
     if (bytes_read != sizeof(pending_data))
       break;
 
     {
       base::AutoLock auto_lock(callback_lock_);
-      if (callback_)
-        callback_->Process(pending_data);
+      if (callback_) {
+        // TODO(acolwell): Update downstream code to use a uint32.
+        // Under normal operation saturation should never occur here
+        // and even if it does, it would only cause a temporary loss
+        // of A/V sync which is much better than crashing or halting
+        // playback.
+        callback_->Process(base::saturated_cast<uint32>(pending_data));
+      }
     }
 
     // Let the other end know which buffer we just filled.  The buffer index is
     // used to ensure the other end is getting the buffer it expects.  For more
     // details on how this works see AudioSyncReader::WaitUntilDataIsReady().
     if (synchronized_buffers_) {
       ++buffer_index;
       size_t bytes_sent = socket_.Send(&buffer_index, sizeof(buffer_index));
       if (bytes_sent != sizeof(buffer_index))
         break;
@@ skipping 24 matching lines @@
 }
 
 AudioDeviceThread::Callback::~Callback() {}
 
 void AudioDeviceThread::Callback::InitializeOnAudioThread() {
   MapSharedMemory();
   CHECK(shared_memory_.memory());
 }
 
 }  // namespace media.