ServiceWorker: Migrate the script cache backend from BlockFile to Simple

content/browser/service_worker/service_worker_disk_cache_migrator.cc

Index: content/browser/service_worker/service_worker_disk_cache_migrator.cc
diff --git a/content/browser/service_worker/service_worker_disk_cache_migrator.cc b/content/browser/service_worker/service_worker_disk_cache_migrator.cc
index ffd5526db2bacc740b02337449ad71f26dcd5dba..7d927d291a9c688edb5d3a81789e62f134bf7a60 100644
--- a/content/browser/service_worker/service_worker_disk_cache_migrator.cc
+++ b/content/browser/service_worker/service_worker_disk_cache_migrator.cc
@@ -5,7 +5,9 @@
 #include "content/browser/service_worker/service_worker_disk_cache_migrator.h"
 
 #include "base/memory/ref_counted.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
+#include "base/time/time.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "net/base/io_buffer.h"
 #include "net/base/net_errors.h"
@@ -13,6 +15,26 @@
 
 namespace content {
 
+namespace {
+
+void RecordMigrationResult(ServiceWorkerStatusCode status) {
+  UMA_HISTOGRAM_ENUMERATION("ServiceWorker.DiskCacheMigrator.MigrationResult",
+                            status, SERVICE_WORKER_ERROR_MAX_VALUE);
+}
+
+void RecordNumberOfMigratedResources(size_t migrated_resources) {
+  UMA_HISTOGRAM_CUSTOM_COUNTS(
+      "ServiceWorker.DiskCacheMigrator.NumberOfMigratedResources",
+      migrated_resources, 1, 1000, 50);
+}
+
+void RecordMigrationTime(const base::TimeDelta& time) {
+  UMA_HISTOGRAM_MEDIUM_TIMES("ServiceWorker.DiskCacheMigrator.MigrationTime",
+                             time);
+}
+
+}  // namespace
+
 // A task to move a cached resource from the src DiskCache to the dest
 // DiskCache. This is owned by ServiceWorkerDiskCacheMigrator.
 class ServiceWorkerDiskCacheMigrator::Task {
@@ -229,6 +251,7 @@ ServiceWorkerDiskCacheMigrator::~ServiceWorkerDiskCacheMigrator() {
 void ServiceWorkerDiskCacheMigrator::Start(const StatusCallback& callback) {
   callback_ = callback;
   iterator_ = src_->disk_cache()->CreateIterator();
+  start_time_ = base::TimeTicks::Now();
   ContinueMigratingResources();
 }
 
@@ -305,6 +328,8 @@ void ServiceWorkerDiskCacheMigrator::OnResourceMigrated(
     return;
   }
 
+  ++number_of_migrated_resources_;
+
   if (pending_task_) {
     RunPendingTask();
     ContinueMigratingResources();
@@ -319,7 +344,11 @@ void ServiceWorkerDiskCacheMigrator::OnResourceMigrated(
 
 void ServiceWorkerDiskCacheMigrator::Complete(ServiceWorkerStatusCode status) {
   DCHECK(inflight_tasks_.IsEmpty());
-  // TODO(nhiroki): Add UMA for the result of migration.
+  if (status == SERVICE_WORKER_OK) {
+    RecordMigrationTime(base::TimeTicks().Now() - start_time_);
+    RecordNumberOfMigratedResources(number_of_migrated_resources_);
+  }
+  RecordMigrationResult(status);
   callback_.Run(status);
 }