Moved struct definition to the header file for the ring buffer.

webrtc/common_audio/ring_buffer.c

Index: webrtc/common_audio/ring_buffer.c
diff --git a/webrtc/common_audio/ring_buffer.c b/webrtc/common_audio/ring_buffer.c
index 60fb5dff20d0a0853bf518f798a6cc6138197231..5fc653bd57e53c774e923e23fd82eaa89a1e775f 100644
--- a/webrtc/common_audio/ring_buffer.c
+++ b/webrtc/common_audio/ring_buffer.c
@@ -17,20 +17,6 @@
 #include <stdlib.h>
 #include <string.h>
 
-enum Wrap {
-  SAME_WRAP,
-  DIFF_WRAP
-};
-
-struct RingBuffer {
-  size_t read_pos;
-  size_t write_pos;
-  size_t element_count;
-  size_t element_size;
-  enum Wrap rw_wrap;
-  char* data;
-};
-
 // Get address of region(s) from which we can read data.
 // If the region is contiguous, |data_ptr_bytes_2| will be zero.
 // If non-contiguous, |data_ptr_bytes_2| will be the size in bytes of the second