Roll chromium_revision b1748b:681cc8

Pick the libvpx roll: https://codereview.chromium.org/513593002

BUG=3747
R=andrew@webrtc.org
TBR=ajm@google.com

Review URL: https://webrtc-codereview.appspot.com/14229004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@6993 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/DEPS b/DEPS
index d9c8e1a..ee73527 100644
--- a/DEPS
+++ b/DEPS
@@ -14,7 +14,7 @@
   # Use this googlecode_url variable only if there is an internal mirror for it.
   # If you do not know, use the full path while defining your new deps entry.
   "googlecode_url": "http://%s.googlecode.com/svn",
-  "chromium_revision": "b1748b82e821777fb8cd843fd54ff3aeb220a215",
+  "chromium_revision": "681cc8e61e5142f490a176e57dba0f2d2a44d14c",
 }
 
 # NOTE: Prefer revision numbers to tags for svn deps. Use http rather than