Update libvpx snapshot to v0.9.7-p1 (Cayuga).

source/libvpx/vp8/decoder/treereader.h

Index: source/libvpx/vp8/decoder/treereader.h
===================================================================
--- source/libvpx/vp8/decoder/treereader.h	(revision 96967)
+++ source/libvpx/vp8/decoder/treereader.h	(working copy)
@@ -38,27 +38,4 @@
     return -i;
 }
 
-
-/* Variant reads a binary number given distributions on each bit.
-   Note that tree is arbitrary; probability of decoding a zero
-   may or may not depend on previously decoded bits. */
-
-static int vp8_treed_read_num(
-    vp8_reader *const r,        /* !!! must return a 0 or 1 !!! */
-    vp8_tree t,
-    const vp8_prob *const p
-)
-{
-    vp8_tree_index i = 0;
-    int v = 0, b;
-
-    do
-    {
-        b = vp8_read(r, p[i>>1]);
-        v = (v << 1) + b;
-    }
-    while ((i = t[i+b]) > 0);
-
-    return v;
-}
 #endif /* tree_reader_h */