[PPAPI] Pepper MediaStream API audio track implementation and example.

ppapi/shared_impl/media_stream_frame_buffer.cc

 // Copyright 2014 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 "ppapi/shared_impl/media_stream_frame_buffer.h"
 
 #include "base/logging.h"
 #include "ppapi/c/pp_errors.h"
 
 namespace ppapi {
@@ skipping 11 matching lines @@
 }
 
 MediaStreamFrameBuffer::~MediaStreamFrameBuffer() {
 }
 
 bool MediaStreamFrameBuffer::SetFrames(
     int32_t number_of_frames,
     int32_t frame_size,
     scoped_ptr<base::SharedMemory> shm,
     bool enqueue_all_frames) {
+  base::AutoLock lock(mutex_);
   DCHECK(shm);
   DCHECK(!shm_);
   DCHECK_GT(number_of_frames, 0);
   DCHECK_GT(frame_size, static_cast<int32_t>(sizeof(MediaStreamFrame::Header)));
   DCHECK_EQ(frame_size & 0x3, 0);
 
   number_of_frames_ = number_of_frames;
   frame_size_ = frame_size;
 
   int32_t size = number_of_frames_ * frame_size;
   shm_ = shm.Pass();
   if (!shm_->Map(size))
     return false;
 
   uint8_t* p = reinterpret_cast<uint8_t*>(shm_->memory());
   for (int32_t i = 0; i < number_of_frames; ++i) {
     if (enqueue_all_frames)
       frame_queue_.push_back(i);
     frames_.push_back(reinterpret_cast<MediaStreamFrame*>(p));
     p += frame_size_;
   }
   return true;
 }
 
 int32_t MediaStreamFrameBuffer::DequeueFrame() {
+  base::AutoLock lock(mutex_);
   if (frame_queue_.empty())
     return PP_ERROR_FAILED;
   int32_t frame = frame_queue_.front();
   frame_queue_.pop_front();
   return frame;
 }
 
 void MediaStreamFrameBuffer::EnqueueFrame(int32_t index) {
   DCHECK_GE(index, 0);
   DCHECK_LT(index, number_of_frames_);
-  frame_queue_.push_back(index);
+  {
+    base::AutoLock lock(mutex_);
+    frame_queue_.push_back(index);
+  }
   delegate_->OnNewFrameEnqueued();
 }
 
 MediaStreamFrame* MediaStreamFrameBuffer::GetFramePointer(
     int32_t index) {
+  base::AutoLock lock(mutex_);
   DCHECK_GE(index, 0);
   DCHECK_LT(index, number_of_frames_);
   return frames_[index];
 }
 
 }  // namespace ppapi