Fixing incorrect memset in mock class.

I got a linker warning, and I could see the memset was clearly
incorrect since the arugment order should be ptr, value, size_t.

BUG=None
R=perkj@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/35269004

Cr-Commit-Position: refs/heads/master@{#8473}
git-svn-id: http://webrtc.googlecode.com/svn/trunk@8473 4adac7df-926f-26a2-2b94-8c16560cd09d
diff --git a/talk/app/webrtc/test/mockpeerconnectionobservers.h b/talk/app/webrtc/test/mockpeerconnectionobservers.h
index 606d485..9b06c2f 100644
--- a/talk/app/webrtc/test/mockpeerconnectionobservers.h
+++ b/talk/app/webrtc/test/mockpeerconnectionobservers.h
@@ -123,7 +123,7 @@
   virtual void OnComplete(const StatsReports& reports) {
     ASSERT(!called_);
     called_ = true;
-    memset(&stats_, sizeof(stats_), 0);
+    memset(&stats_, 0, sizeof(stats_));
     stats_.number_of_reports = reports.size();
     for (const auto* r : reports) {
       if (r->type() == StatsReport::kStatsReportTypeSsrc) {