Introduce ServiceWorker.MainFramePageLoad.CoreTransition and RedirectChainLength UMAs.

content/browser/service_worker/service_worker_metrics.cc

Index: content/browser/service_worker/service_worker_metrics.cc
diff --git a/content/browser/service_worker/service_worker_metrics.cc b/content/browser/service_worker/service_worker_metrics.cc
index 310e76e3d8a69cf6821c14c13f66bb4ec0810e69..0efb7bb4255828fe1c33fc784ee63023af92fea4 100644
--- a/content/browser/service_worker/service_worker_metrics.cc
+++ b/content/browser/service_worker/service_worker_metrics.cc
@@ -321,9 +321,12 @@ void ServiceWorkerMetrics::RecordDeleteAndStartOverResult(
                             result, NUM_DELETE_AND_START_OVER_RESULT_TYPES);
 }
 
-void ServiceWorkerMetrics::CountControlledPageLoad(Site site,
-                                                   const GURL& url,
-                                                   bool is_main_frame_load) {
+void ServiceWorkerMetrics::CountControlledPageLoad(
+    Site site,
+    const GURL& url,
+    bool is_main_frame_load,
+    ui::PageTransition page_transition,
+    size_t redirect_chain_length) {
   DCHECK_NE(site, Site::OTHER);
   UMA_HISTOGRAM_ENUMERATION("ServiceWorker.PageLoad", static_cast<int>(site),
                             static_cast<int>(Site::NUM_TYPES));
@@ -332,9 +335,20 @@ void ServiceWorkerMetrics::CountControlledPageLoad(Site site,
                               static_cast<int>(site),
                               static_cast<int>(Site::NUM_TYPES));
   }
-
   if (ShouldExcludeSiteFromHistogram(site))
     return;
+
+  if (is_main_frame_load) {
+    UMA_HISTOGRAM_ENUMERATION(
+        "ServiceWorker.MainFramePageLoad.CoreTransition",
+        static_cast<int>(ui::PageTransitionStripQualifier(page_transition)),
+        static_cast<int>(ui::PAGE_TRANSITION_LAST_CORE) + 1);
+    // Currently the max number of HHTP redirects is 20. So the max number of

[shimazu, 2016/12/07 01:18:51]

nit: HTTP redirects? and how about adding "as |kMaxRedirects| in
url_request.cc." to the comment for reference?

[horo, 2016/12/07 01:26:49]

Fixed "HHTP".
I incorporated mmenke@'s comment.
https://codereview.chromium.org/2551013003/#msg36

[falken, 2016/12/07 01:28:49]

It makes sense to hardcode it as per mmenke, but +1 to adding the comment about
where the 20 is defined.

[horo, 2016/12/07 01:58:34]

Done.

+    // the chain length is 21.
+    UMA_HISTOGRAM_EXACT_LINEAR(
+        "ServiceWorker.MainFramePageLoad.RedirectChainLength",
+        redirect_chain_length, 21);
+  }
   BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
                           base::Bind(&RecordURLMetricOnUI, url));
 }