Promote Scroll Anchoring to experimental

third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in

 // http://dev.chromium.org/blink/runtime-enabled-features
 //
 // This list is used to generate RuntimeEnabledFeatures.h/cpp which contains
 // a class that stores static enablers for all experimental features.
 //
 // Each feature can be assigned a "status":
 // status=stable -> Enable this in all Blink configurations.  We are committed to these APIs indefinitely.
 // status=experimental -> In-progress features, Web Developers might play with, but are not on by default in stable.
 // status=test -> Enabled in ContentShell for testing, otherwise off.
 // Features without a status are not enabled anywhere by default.
@@ skipping 173 matching lines @@
 RenderingPipelineThrottling status=stable
 RenderUnicodeControlCharacters status=experimental
 RequestIdleCallback status=stable
 ResizeObserver status=experimental
 // Handles frame scrolling via the root PaintLayer instead of the FrameView.
 // crbug.com/417782 tracks enabling this by default.
 RootLayerScrolling
 RTCPeerConnectionNewGetStats status=test
 ScriptedSpeech status=stable
 // Scrolls to compensate for layout movements (bit.ly/scroll-anchoring).
-ScrollAnchoring settable_from_internals=True
+ScrollAnchoring status=experimental, settable_from_internals=True

[ojan, 2016/09/13 21:52:09]

IIRC, experimental just means that it'll be enabled for anyone who turns on the
--enabled-experimental-web-platform-features flag. Is that what you were going
for? If not, I think you want status=stable.

 // Implements documentElement.scrollTop/Left and bodyElement.scrollTop/Left
 // as per the spec, matching other Web engines.
 ScrollTopLeftInterop status=experimental
 Sensor status=experimental
 ServiceWorkerClientAttributes status=stable
 ServiceWorkerClientsGetID status=stable
 ServiceWorkerWindowClientNavigate status=stable
 SetRootScroller status=experimental
 ShadowDOMV1 status=stable
 SharedArrayBuffer
@@ skipping 46 matching lines @@
 AutoplayMutedVideos settable_from_internals=True
 VisualViewportAPI status=experimental
 WakeLock status=experimental
 WebFontsInterventionV2With2G
 WebFontsInterventionV2WithSlow2G
 WebFontsInterventionTrigger
 WebShare status=experimental, origin_trial_feature_name=WebShare
 Worklet status=experimental
 ParseHTMLOnMainThread status=test
 SendBeaconThrowForBlobWithNonSimpleType status=experimental