Presentation API: mark the feature as stable.

Intent to Ship:
https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/YKVnS429hns

BUG=412331
NOTRY=true

Review URL: https://codereview.chromium.org/1315103002

git-svn-id: svn://svn.chromium.org/blink/trunk@201233 bbb929c8-8fbe-4397-9dbb-9b2b20218538

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

@@ -3017,6 +3017,7 @@ interface Navigator
     getter permissions
     getter platform
     getter plugins
+    getter presentation
     getter product
     getter productSub
     getter serviceWorker
@@ -3280,6 +3281,38 @@ interface PluginArray
 interface PopStateEvent
     getter state
     method constructor
+interface Presentation
+    getter defaultRequest
+    getter session
+    method constructor
+    setter defaultRequest
+interface PresentationAvailability
+    getter onchange
+    getter value
+    method constructor
+    setter onchange
+interface PresentationRequest
+    getter onsessionconnect
+    method constructor
+    method getAvailability
+    method join
+    method start
+    setter onsessionconnect
+interface PresentationSession
+    getter binaryType
+    getter id
+    getter onmessage
+    getter onstatechange
+    getter state
+    method close
+    method constructor
+    method send
+    setter binaryType
+    setter onmessage
+    setter onstatechange
+interface PresentationSessionConnectEvent
+    getter session
+    method constructor
 interface ProcessingInstruction
     getter sheet
     getter target

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in

@@ -125,7 +125,7 @@ PrefixedEncryptedMedia status=stable
 // This feature is deprecated and we are evangalizing affected sites.
 // See https://crbug.com/346236 for current status.
 PrefixedVideoFullscreen status=stable
-Presentation status=experimental
+Presentation status=stable
 PromiseRejectionEvent status=experimental
 PushMessaging status=stable
 // Push messaging payloads are blocked on the Push API supporting encryption.