[BackgroundSync] Enable BackgroundSync by default

Intent to ship: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/t9apD7cQb6I

BUG=449443

Review URL: https://codereview.chromium.org/1514383002

Cr-Commit-Position: refs/heads/master@{#364709}
diff --git a/third_party/WebKit/LayoutTests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt b/third_party/WebKit/LayoutTests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt
index 16c3978..574757f 100644
--- a/third_party/WebKit/LayoutTests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt
+++ b/third_party/WebKit/LayoutTests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt
@@ -477,6 +477,7 @@
     getter onupdatefound
     getter pushManager
     getter scope
+    getter sync
     method constructor
     method getNotifications
     method showNotification
@@ -497,6 +498,14 @@
     method unwrapKey
     method verify
     method wrapKey
+interface SyncEvent : ExtendableEvent
+    getter lastChance
+    getter tag
+    method constructor
+interface SyncManager
+    method constructor
+    method getTags
+    method register
 interface TextDecoder
     getter encoding
     getter fatal
@@ -741,6 +750,7 @@
     getter onmessage
     getter onnotificationclick
     getter onpush
+    getter onsync
     getter registration
     method close
     method fetch
@@ -752,6 +762,7 @@
     setter onmessage
     setter onnotificationclick
     setter onpush
+    setter onsync
 This is a testharness.js-based test.
 PASS Verify the interface of ServiceWorkerGlobalScope 
 Harness: the test ran to completion.
diff --git a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt
index 9a6ee82..41463b5 100644
--- a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt
+++ b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt
@@ -462,6 +462,7 @@
 [Worker]     getter onupdatefound
 [Worker]     getter pushManager
 [Worker]     getter scope
+[Worker]     getter sync
 [Worker]     method constructor
 [Worker]     method getNotifications
 [Worker]     method showNotification
diff --git a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
index 4407159..b81d32a 100644
--- a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
+++ b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt
@@ -4511,6 +4511,7 @@
     getter onupdatefound
     getter pushManager
     getter scope
+    getter sync
     method constructor
     method getNotifications
     method showNotification
@@ -4613,6 +4614,10 @@
     method unwrapKey
     method verify
     method wrapKey
+interface SyncManager
+    method constructor
+    method getTags
+    method register
 interface Text : CharacterData
     getter wholeText
     method constructor
diff --git a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt
index 7f759d0..6a8e5fda 100644
--- a/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt
+++ b/third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt
@@ -452,6 +452,7 @@
 [Worker]     getter onupdatefound
 [Worker]     getter pushManager
 [Worker]     getter scope
+[Worker]     getter sync
 [Worker]     method constructor
 [Worker]     method getNotifications
 [Worker]     method showNotification
diff --git a/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in b/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
index 03d5e93..8497632 100644
--- a/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
+++ b/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
@@ -27,8 +27,7 @@
 AudioOutputDevices status=experimental
 AudioVideoTracks depends_on=Media, status=experimental
 AuthorShadowDOMForAnyElement
-BackgroundSync status=experimental
-BackgroundSyncPeriodic status=experimental
+BackgroundSync status=stable
 BackgroundSyncV2 status=experimental
 CacheStorageMatchAll status=stable
 ClientHints status=stable