Promote NotificationBadge to stable.

Intent to ship: http://bit.ly/295ZVHZ

BUG=591394

Review-Url: https://codereview.chromium.org/2108723003
Cr-Commit-Position: refs/heads/master@{#403258}

third_party/WebKit/LayoutTests/virtual/stable/http/tests/serviceworker/webexposed/global-interface-listing-service-worker-expected.txt

@@ -416,6 +416,7 @@ interface Notification : EventTarget
     static getter maxActions
     static getter permission
     getter actions
+    getter badge
     getter body
     getter data
     getter dir

third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-dedicated-worker-expected.txt

@@ -447,6 +447,7 @@ Starting worker: resources/global-interface-listing.js
 [Worker]     static getter permission
 [Worker]     attribute @@toStringTag
 [Worker]     getter actions
+[Worker]     getter badge
 [Worker]     getter body
 [Worker]     getter data
 [Worker]     getter dir

third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-expected.txt

@@ -3509,6 +3509,7 @@ interface Notification : EventTarget
     static method requestPermission
     attribute @@toStringTag
     getter actions
+    getter badge
     getter body
     getter data
     getter dir

third_party/WebKit/LayoutTests/virtual/stable/webexposed/global-interface-listing-shared-worker-expected.txt

@@ -434,6 +434,7 @@ Starting worker: resources/global-interface-listing.js
 [Worker]     static getter permission
 [Worker]     attribute @@toStringTag
 [Worker]     getter actions
+[Worker]     getter badge
 [Worker]     getter body
 [Worker]     getter data
 [Worker]     getter dir

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in

@@ -136,7 +136,7 @@ NetworkInformation status=stable
 NetInfoDownlinkMax status=stable
 NewMediaPlaybackUi
 NotificationConstructor status=stable
-NotificationBadge status=experimental
+NotificationBadge status=stable
 NotificationInlineReplies status=experimental
 Notifications status=stable
 OnDeviceChange status=experimental