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 3b31d31b64263fc601345a188e3c2caf4fa6a59d..f5e71cc087cbc49d0558fa60579b35f7b286a876 100644
--- a/content/browser/service_worker/service_worker_disk_cache_migrator.cc
+++ b/content/browser/service_worker/service_worker_disk_cache_migrator.cc
@@ -8,8 +8,10 @@
 #include "base/files/file_util.h"
 #include "base/location.h"
 #include "base/memory/ref_counted.h"
+#include "base/metrics/histogram_macros.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/task_runner_util.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"
@@ -22,6 +24,22 @@ namespace {
 // Disk cache entry data indices (Copied from appcache_diskcache.cc).
 enum { kResponseInfoIndex, kResponseContentIndex, kResponseMetadataIndex };
 
+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
@@ -245,6 +263,8 @@ ServiceWorkerDiskCacheMigrator::~ServiceWorkerDiskCacheMigrator() {
 
 void ServiceWorkerDiskCacheMigrator::Start(const StatusCallback& callback) {
   callback_ = callback;
+  start_time_ = base::TimeTicks::Now();
+
   PostTaskAndReplyWithResult(
       disk_cache_thread_.get(), FROM_HERE,
       base::Bind(&base::DeleteFile, dest_path_, true),
@@ -403,6 +423,8 @@ void ServiceWorkerDiskCacheMigrator::OnEntryMigrated(
     return;
   }
 
+  ++number_of_migrated_resources_;
+
   if (pending_task_) {
     RunPendingTask();
     OpenNextEntry();
@@ -418,7 +440,11 @@ void ServiceWorkerDiskCacheMigrator::OnEntryMigrated(
 
 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);
 
   src_.reset();
   dest_.reset();