Implementation of 'AudioContext.getOutputTimestamp' method

media/audio/audio_device_thread.h

Index: media/audio/audio_device_thread.h
diff --git a/media/audio/audio_device_thread.h b/media/audio/audio_device_thread.h
index 61e5e8724ddc24b289c01c364e3491b137779462..6507efd1c7eed6c38eca9fce6d2e9f3d41a1d019 100644
--- a/media/audio/audio_device_thread.h
+++ b/media/audio/audio_device_thread.h
@@ -12,6 +12,7 @@
 #include "base/memory/shared_memory.h"
 #include "base/sync_socket.h"
 #include "base/synchronization/lock.h"
+#include "media/audio/audio_io.h"
 #include "media/base/audio_parameters.h"
 #include "media/base/media_export.h"
 
@@ -21,6 +22,7 @@ class MessageLoop;
 
 namespace media {
 class AudioBus;
+struct AudioTimestamp;
 
 // Data transfer between browser and render process uses a combination
 // of sync sockets and shared memory. To read from the socket and render
@@ -52,7 +54,9 @@ class MEDIA_EXPORT AudioDeviceThread {
     virtual void MapSharedMemory() = 0;
 
     // Called whenever we receive notifications about pending input data.
-    virtual void Process(uint32_t pending_data) = 0;
+    // It also provides the current audio stream timestamp on the device.
+    virtual void Process(uint32_t pending_data,
+                         const AudioTimestamp& timestamp) = 0;
 
    protected:
     // Protected so that derived classes can access directly.
@@ -75,6 +79,12 @@ class MEDIA_EXPORT AudioDeviceThread {
   AudioDeviceThread();
   ~AudioDeviceThread();
 
+  // Represents a data packet to be received via the socket.
+  struct Packet {
+    uint32_t pending_data;
+    AudioTimestamp timestamp;
+  };
+
   // Starts the audio thread. The thread must not already be running.  If
   // |sychronized_buffers| is set, the browser expects to be notified via the
   // |socket| every time AudioDeviceThread::Process() completes.