Roll opus to 172355 and delete opus_demo from webrtc opus

opus_demo has been inlucded in opus in chromium.

BUG=None
TEST=trybots
Review URL: https://webrtc-codereview.appspot.com/973013

git-svn-id: http://webrtc.googlecode.com/svn/trunk@3317 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/DEPS b/DEPS
index c626553..2479da6 100644
--- a/DEPS
+++ b/DEPS
@@ -58,10 +58,10 @@
     (Var("googlecode_url") % "libyuv") + "/trunk@520",
 
   "third_party/opus":
-    Var("chromium_trunk") + "/src/third_party/opus@165570",
+    Var("chromium_trunk") + "/src/third_party/opus@172355",
 
   "third_party/opus/src":
-    Var("chromium_trunk") + "/deps/third_party/opus@165487",
+    Var("chromium_trunk") + "/deps/third_party/opus@173498",
 
   "third_party/protobuf":
     Var("chromium_trunk") + "/src/third_party/protobuf@" + Var("chromium_revision"),