Audio input debug recording refactoring to reduce thread hops and simplify object ownership

media/audio/audio_input_writer.h

Index: media/audio/audio_input_writer.h
diff --git a/media/audio/audio_input_writer.h b/media/audio/audio_input_writer.h
index 42ca0ba42d6e43c10445261355d6e4bc0f00d4f6..9e9f9a723489c7f1b8c8fef6229cc7e958ec0690 100644
--- a/media/audio/audio_input_writer.h
+++ b/media/audio/audio_input_writer.h
@@ -17,8 +17,23 @@ class AudioInputWriter {
  public:
   virtual ~AudioInputWriter() {}
 
+  // Must be called before calling Write() for the first time after creation or
+  // Stop() call. Can be called on any sequence; Write() and Stop() must be
+  // called on the same sequence as Start().
+  virtual void Start(const base::FilePath& file) = 0;
+
+  // Must be called to finish recording. Each call to Start() requires a call to
+  // Stop(). Will be automatically called on destruction.
+  virtual void Stop() = 0;
+
   // Write |data| to file.
   virtual void Write(std::unique_ptr<AudioBus> data) = 0;
+
+  // Returns true if Write() call scheduled at this point will most likely write
+  // data to the file, and false if it most likely will be a no-op. The result
+  // may be ambigulous if Start() or Stop() is executed at the moment. Can be
+  // called from any sequence.
+  virtual bool WillWrite() = 0;
 };
 
 }  // namspace media