Bug 1413512 -- Added a telemtry for counting of the HTTP redirection that triggered by top-level document or by subresource. r=schien data=francois

netwerk/protocol/http/nsHttpHandler.cpp

@@ -119,6 +119,8 @@
 
 //-----------------------------------------------------------------------------
 
+using mozilla::Telemetry::LABELS_NETWORK_HTTP_REDIRECT_TO_SCHEME;
+
 namespace mozilla {
 namespace net {
 
@@ -828,14 +830,28 @@ nsHttpHandler::AsyncOnChannelRedirect(nsIChannel* oldChan,
                                       uint32_t flags,
                                       nsIEventTarget* mainThreadEventTarget)
 {
-    // TODO E10S This helper has to be initialized on the other process
-    RefPtr<nsAsyncRedirectVerifyHelper> redirectCallbackHelper =
-        new nsAsyncRedirectVerifyHelper();
+  MOZ_ASSERT(NS_IsMainThread() && (oldChan && newChan));
 
-    return redirectCallbackHelper->Init(oldChan,
-                                        newChan,
-                                        flags,
-                                        mainThreadEventTarget);
+  nsCOMPtr<nsIURI> newURI;
+  newChan->GetURI(getter_AddRefs(newURI));
+  MOZ_ASSERT(newURI);
+
+  nsAutoCString scheme;
+  newURI->GetScheme(scheme);
+  MOZ_ASSERT(!scheme.IsEmpty());
+
+  Telemetry::AccumulateCategoricalKeyed(
+    scheme,
+    oldChan->IsDocument()
+      ? LABELS_NETWORK_HTTP_REDIRECT_TO_SCHEME::topLevel
+      : LABELS_NETWORK_HTTP_REDIRECT_TO_SCHEME::subresource);
+
+  // TODO E10S This helper has to be initialized on the other process
+  RefPtr<nsAsyncRedirectVerifyHelper> redirectCallbackHelper =
+    new nsAsyncRedirectVerifyHelper();
+
+  return redirectCallbackHelper->Init(
+    oldChan, newChan, flags, mainThreadEventTarget);
 }
 
 /* static */ nsresult

toolkit/components/telemetry/Histograms.json

@@ -2383,6 +2383,16 @@
     "labels": ["NotSent", "CachedContentUsed", "CachedContentNotUsed"],
     "description": "Stats for validation requests when cache won the race."
   },
+  "NETWORK_HTTP_REDIRECT_TO_SCHEME" :{
+    "record_in_processes": ["main"],
+    "alert_emails": ["necko@mozilla.com", "seceng-telemetry@mozilla.com", "jkt@mozilla.com"],
+    "bug_numbers": [1413512],
+    "expires_in_version": "64",
+    "kind": "categorical",
+    "keyed": true,
+    "description": "Count of the HTTP redirection that triggered by top-level document or by subresource, keyed by the URL scheme redirected to.",
+    "labels": ["topLevel", "subresource"]
+  },
   "HTTP_AUTH_DIALOG_STATS_3": {
     "record_in_processes": ["main", "content"],
     "expires_in_version": "61",