[Not for review] record detailed time breakdown of SW related requests.

content/browser/service_worker/service_worker_context_request_handler.cc

Index: content/browser/service_worker/service_worker_context_request_handler.cc
diff --git a/content/browser/service_worker/service_worker_context_request_handler.cc b/content/browser/service_worker/service_worker_context_request_handler.cc
index 867752162c373d591d87763817ec2e62387f86d9..1bfbbc95fcb0f6cbcbcf8dc1ad17bca625b0bf78 100644
--- a/content/browser/service_worker/service_worker_context_request_handler.cc
+++ b/content/browser/service_worker/service_worker_context_request_handler.cc
@@ -4,6 +4,7 @@
 
 #include "content/browser/service_worker/service_worker_context_request_handler.h"
 
+#include "base/metrics/histogram_macros.h"
 #include "base/time/time.h"
 #include "content/browser/service_worker/service_worker_context_core.h"
 #include "content/browser/service_worker/service_worker_provider_host.h"
@@ -45,12 +46,18 @@ ServiceWorkerContextRequestHandler::ServiceWorkerContextRequestHandler(
     base::WeakPtr<ServiceWorkerContextCore> context,
     base::WeakPtr<ServiceWorkerProviderHost> provider_host,
     base::WeakPtr<storage::BlobStorageContext> blob_storage_context,
-    ResourceType resource_type)
+    ResourceType resource_type,
+    base::TimeTicks request_start)
     : ServiceWorkerRequestHandler(context,
                                   provider_host,
                                   blob_storage_context,
                                   resource_type),
-      version_(provider_host_->running_hosted_version()) {
+      version_(provider_host_->running_hosted_version()),
+      creation_time(base::TimeTicks::Now()) {
+  if (resource_type != RESOURCE_TYPE_SERVICE_WORKER) {
+    UMA_HISTOGRAM_TIMES("SWF.B2.Request.RendererMainToBrowser",
+                        this->creation_time - request_start);
+  }
   DCHECK(provider_host_->IsHostToRunningServiceWorker());
 }