[bfcache] Track presence of IndexedDB connection for bfcache metrics

In addition to tracking of outstanding IndexedDB transactions, also
track database transactions.

R=haraken@chromium.org,dmurph@chromium.org
BUG=966056

Change-Id: I4c426e3866c74a36b3dc2be1a62c52cb5a7f77b9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1625120
Commit-Queue: Alexander Timin <altimin@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Daniel Murphy <dmurph@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662457}

third_party/blink/public/common/scheduler/web_scheduler_tracked_feature.h

@@ -59,7 +59,9 @@ enum class WebSchedulerTrackedFeature {
 
   kBroadcastChannel = 27,
 
-  kMaxValue = kBroadcastChannel
+  kIndexedDBConnection = 28,
+
+  kMaxValue = kIndexedDBConnection
 };
 
 }  // namespace scheduler

third_party/blink/renderer/modules/indexeddb/idb_database.cc

@@ -101,7 +101,13 @@ IDBDatabase::IDBDatabase(ExecutionContext* context,
       event_queue_(
           MakeGarbageCollected<EventQueue>(context, TaskType::kDatabaseAccess)),
       database_callbacks_(callbacks),
-      isolate_(isolate) {
+      isolate_(isolate),
+      feature_handle_for_scheduler_(
+          context
+              ? context->GetScheduler()->RegisterFeature(
+                    SchedulingPolicy::Feature::kIndexedDBConnection,
+                    {SchedulingPolicy::RecordMetricsForBackForwardCache()})
+              : FrameOrWorkerScheduler::SchedulingAffectingFeatureHandle()) {
   database_callbacks_->Connect(this);
 }
 
@@ -436,6 +442,7 @@ void IDBDatabase::close() {
     return;
 
   close_pending_ = true;
+  feature_handle_for_scheduler_.reset();
 
   if (transactions_.IsEmpty())
     CloseConnection();

third_party/blink/renderer/modules/indexeddb/idb_database.h

@@ -46,6 +46,7 @@
 #include "third_party/blink/renderer/modules/modules_export.h"
 #include "third_party/blink/renderer/platform/bindings/script_state.h"
 #include "third_party/blink/renderer/platform/heap/handle.h"
+#include "third_party/blink/renderer/platform/scheduler/public/frame_or_worker_scheduler.h"
 
 namespace blink {
 
@@ -194,6 +195,9 @@ class MODULES_EXPORT IDBDatabase final
   // Maintain the isolate so that all externally allocated memory can be
   // registered against it.
   v8::Isolate* isolate_;
+
+  FrameOrWorkerScheduler::SchedulingAffectingFeatureHandle
+      feature_handle_for_scheduler_;
 };
 
 }  // namespace blink

third_party/blink/renderer/platform/scheduler/common/scheduling_policy.cc

@@ -17,6 +17,7 @@ bool SchedulingPolicy::IsFeatureSticky(SchedulingPolicy::Feature feature) {
     case Feature::kOutstandingIndexedDBTransaction:
     case Feature::kHasScriptableFramesInMultipleTabs:
     case Feature::kBroadcastChannel:
+    case Feature::kIndexedDBConnection:
       return false;
     case Feature::kMainResourceHasCacheControlNoStore:
     case Feature::kMainResourceHasCacheControlNoCache: