Add a dummy variable to ResourceMsg_DataReceived.

content/child/resource_dispatcher.h

Index: content/child/resource_dispatcher.h
diff --git a/content/child/resource_dispatcher.h b/content/child/resource_dispatcher.h
index 864b081ddca15f45ce9704dd16e205055685bdb5..a262de97313508d67e8fffafbacc595d15372b0f 100644
--- a/content/child/resource_dispatcher.h
+++ b/content/child/resource_dispatcher.h
@@ -190,7 +190,10 @@ class CONTENT_EXPORT ResourceDispatcher : public IPC::Listener {
                        base::SharedMemoryHandle shm_handle,
                        int shm_size,
                        base::ProcessId renderer_pid);
+  // TODO(erikchen): This dummy variable is temporary and is only intended to be
+  // present for one Canary release. http://crbug.com/527588.
   void OnReceivedData(int request_id,
+                      int /* dummy variable */,
                       int data_offset,
                       int data_length,
                       int encoded_data_length);