MediaStream Recorder: add usage counter to WebRTC.webkitApiCount UMA

content/renderer/media/webrtc_uma_histograms.cc

Index: content/renderer/media/webrtc_uma_histograms.cc
diff --git a/content/renderer/media/webrtc_uma_histograms.cc b/content/renderer/media/webrtc_uma_histograms.cc
index 616ff91251405a4914ea8737e0914b9743cce057..a7116960357c1500304b563f1c9da82d70fb8ce4 100644
--- a/content/renderer/media/webrtc_uma_histograms.cc
+++ b/content/renderer/media/webrtc_uma_histograms.cc
@@ -64,8 +64,8 @@ void PerSessionWebRTCAPIMetrics::LogUsageOnlyOnce(JavaScriptAPIName api_name) {
 }
 
 void PerSessionWebRTCAPIMetrics::ResetUsage() {
-  for (size_t i = 0; i < arraysize(has_used_api_); ++i)
-    has_used_api_[i] = false;
+  for (bool& has_used_api : has_used_api_)
+    has_used_api = false;
 }
 
 }  // namespace content