Enhance AudioSplicer to crossfade marked splice frames.

media/base/decoder_buffer.h

Index: media/base/decoder_buffer.h
diff --git a/media/base/decoder_buffer.h b/media/base/decoder_buffer.h
index 393e586d06bfdc2f42b178db6f72250a4b960801..ec32961b5ef04f117a4953dd445005f54454330d 100644
--- a/media/base/decoder_buffer.h
+++ b/media/base/decoder_buffer.h
@@ -130,6 +130,17 @@ class MEDIA_EXPORT DecoderBuffer
     return data_ == NULL;
   }
 
+  // Is this buffer preroll before a splice frame?
+  bool splice_preroll() const {
+    DCHECK(!end_of_stream());
+    return splice_preroll_;
+  }
+
+  void set_splice_preroll(bool splice_preroll) {
+    DCHECK(!end_of_stream());
+    splice_preroll_ = splice_preroll;
+  }
+
   // Returns a human-readable string describing |*this|.
   std::string AsHumanReadableString();
 
@@ -153,6 +164,7 @@ class MEDIA_EXPORT DecoderBuffer
   scoped_ptr<uint8, base::ScopedPtrAlignedFree> side_data_;
   scoped_ptr<DecryptConfig> decrypt_config_;
   base::TimeDelta discard_padding_;
+  bool splice_preroll_;
 
   // Constructor helper method for memory allocations.
   void Initialize();