[cc] Remove remaining_frames from BeginFrameAck.

cc/test/begin_frame_args_test.cc

Index: cc/test/begin_frame_args_test.cc
diff --git a/cc/test/begin_frame_args_test.cc b/cc/test/begin_frame_args_test.cc
index fdc28f1d297d1737d0b957db24af938a59668baa..a2752621bd9f04cadc7ea303352c6e7bbcce596f 100644
--- a/cc/test/begin_frame_args_test.cc
+++ b/cc/test/begin_frame_args_test.cc
@@ -98,7 +98,6 @@ bool operator==(const BeginFrameAck& lhs, const BeginFrameAck& rhs) {
          (lhs.sequence_number == rhs.sequence_number) &&
          (lhs.latest_confirmed_sequence_number ==
           rhs.latest_confirmed_sequence_number) &&
-         (lhs.remaining_frames == rhs.remaining_frames) &&
          (lhs.has_damage == rhs.has_damage);
 }
 
@@ -109,8 +108,8 @@ bool operator==(const BeginFrameAck& lhs, const BeginFrameAck& rhs) {
 
 void PrintTo(const BeginFrameAck& ack, ::std::ostream* os) {
   *os << "BeginFrameAck(" << ack.source_id << ", " << ack.sequence_number
-      << ", " << ack.latest_confirmed_sequence_number << ", "
-      << ack.remaining_frames << ", " << ack.has_damage << ")";
+      << ", " << ack.latest_confirmed_sequence_number << ", " << ack.has_damage
+      << ")";
 }
 
 }  // namespace cc