Turn SourceBufferChangeTypeEnabled on by default
[WebKit-https.git] / Source / WebCore / page / Settings.yaml
1 # FIXME: Add support for global settings.
2 # FIXME: Add support for custom getters/setters.
3
4 defaultTextEncodingName:
5   type: String
6 ftpDirectoryTemplatePath:
7   type: String
8 localStorageDatabasePath:
9   type: String
10 editableLinkBehavior:
11   type: EditableLinkBehavior
12   initial: EditableLinkDefaultBehavior
13 textDirectionSubmenuInclusionBehavior:
14   type: TextDirectionSubmenuInclusionBehavior
15   initial: TextDirectionSubmenuAutomaticallyIncluded
16 pdfImageCachingPolicy:
17   type: PDFImageCachingPolicy
18   initial: PDFImageCachingDefault
19 passwordEchoDurationInSeconds:
20   type: double
21   initial: 1
22
23 # Sets the magnification value for validation message timer.  If the
24 # magnification value is N, a validation message disappears automatically after
25 # <message length> * N / 1000 seconds.  If N is equal to or less than 0, a
26 # validation message doesn't disappears automaticaly.
27 validationMessageTimerMagnification:
28   type: int
29   initial: 50
30
31 # Number of pixels below which 2D canvas is rendered in software
32 # even if hardware acceleration is enabled.
33 # Hardware acceleration is useful for large canvases where it can avoid the
34 # pixel bandwidth between the CPU and GPU. But GPU acceleration comes at
35 # a price - extra back-buffer and texture copy. Small canvases are also
36 # widely used for stylized fonts. Anti-aliasing text in hardware at that
37 # scale is generally slower. So below a certain size it is better to
38 # draw canvas in software.
39 minimumAccelerated2dCanvasSize:
40   type: int
41   initial: 257*256
42
43 maximumAccelerated2dCanvasSize:
44   type: unsigned
45   initial: 5120*2880
46
47 layoutFallbackWidth:
48   type: int
49   initial: 980
50 deviceWidth:
51   type: int
52   initial: 0
53 deviceHeight:
54   type: int
55   initial: 0
56
57 # Allow clients concerned with memory consumption to set a quota on session storage
58 # since the memory used won't be released until the Page is destroyed.
59 sessionStorageQuota:
60   type: unsigned
61   initial: StorageMap::noQuota
62
63 minimumFontSize:
64   type: int
65   initial: 0
66   onChange: setNeedsRecalcStyleInAllFrames
67 minimumLogicalFontSize:
68   type: int
69   initial: 0
70   onChange: setNeedsRecalcStyleInAllFrames
71 defaultFontSize:
72   type: int
73   initial: 16
74   onChange: setNeedsRecalcStyleInAllFrames
75 defaultFixedFontSize:
76   type: int
77   initial: 0
78   onChange: setNeedsRecalcStyleInAllFrames
79
80 editingBehaviorType:
81   type: EditingBehaviorType
82   initial: editingBehaviorTypeForPlatform()
83 maximumHTMLParserDOMTreeDepth:
84   type: unsigned
85   initial: defaultMaximumHTMLParserDOMTreeDepth
86
87 # This setting only affects site icon image loading if loadsImagesAutomatically setting is false and this setting is true.
88 # All other permutations still heed loadsImagesAutomatically setting.
89 loadsSiteIconsIgnoringImageLoadingSetting:
90   initial: false
91
92 caretBrowsingEnabled:
93   initial: false
94 preventKeyboardDOMEventDispatch:
95   initial: false
96 localStorageEnabled:
97   initial: false
98 allowUniversalAccessFromFileURLs:
99   initial: true
100 allowFileAccessFromFileURLs:
101   initial: true
102 allowSettingAnyXHRHeaderFromFileURLs:
103   initial: false
104 allowCrossOriginSubresourcesToAskForCredentials:
105   initial: false
106 needsStorageAccessFromFileURLsQuirk:
107   initial: true
108 needsFrameNameFallbackToIdQuirk:
109   initial: false
110 useAnonymousModeWhenFetchingMaskImages:
111   initial: true
112 javaScriptCanOpenWindowsAutomatically:
113   initial: false
114 javaScriptCanAccessClipboard:
115   initial: false
116 shouldPrintBackgrounds:
117   initial: false
118 usesDashboardBackwardCompatibilityMode:
119   initial: false
120   conditional: DASHBOARD_SUPPORT
121 clipboardAccessPolicy:
122   type: ClipboardAccessPolicy
123   initial: ClipboardAccessPolicy::RequiresUserGesture
124
125 textAreasAreResizable:
126   initial: false
127   onChange: setNeedsRecalcStyleInAllFrames
128 authorAndUserStylesEnabled:
129   initial: true
130   onChange: setNeedsRecalcStyleInAllFrames
131 userStyleSheetLocation:
132   type: URL
133   onChange: userStyleSheetLocationChanged
134 acceleratedCompositingEnabled:
135   initial: true
136   onChange: setNeedsRecalcStyleInAllFrames
137 acceleratedCompositedAnimationsEnabled:
138   initial: true
139   onChange: setNeedsRecalcStyleInAllFrames
140 showDebugBorders:
141   initial: false
142   onChange: setNeedsRecalcStyleInAllFrames
143 showRepaintCounter:
144   initial: false
145   onChange: setNeedsRecalcStyleInAllFrames
146 visibleDebugOverlayRegions:
147   type: DebugOverlayRegions
148   initial: 0
149 showTiledScrollingIndicator:
150   initial: false
151 resourceUsageOverlayVisible:
152   initial: false
153   onChange: resourceUsageOverlayVisibleChanged
154   condition: RESOURCE_USAGE
155 disableScreenSizeOverride:
156   initial: false
157
158 # This is a quirk we are pro-actively applying to old applications. It changes keyboard event dispatching,
159 # making keyIdentifier available on keypress events, making charCode available on keydown/keyup events,
160 # and getting keypress dispatched in more cases.
161 needsKeyboardEventDisambiguationQuirks:
162   initial: false
163
164 treatsAnyTextCSSLinkAsStylesheet:
165   initial: false
166 shrinksStandaloneImagesToFit:
167   initial: true
168 pageCacheSupportsPlugins:
169   initial: false
170 showsURLsInToolTips:
171   initial: false
172 showsToolTipOverTruncatedText:
173   initial: false
174 forceFTPDirectoryListings:
175   initial: false
176 developerExtrasEnabled:
177   initial: false
178 scriptMarkupEnabled:
179   initial: true
180 needsSiteSpecificQuirks:
181   initial: false
182 domTimersThrottlingEnabled:
183   initial: true
184 webArchiveDebugModeEnabled:
185   initial: false
186   conditional: WEB_ARCHIVE
187 localFileContentSniffingEnabled:
188   initial: false
189 offlineWebApplicationCacheEnabled:
190   initial: false
191 enforceCSSMIMETypeInNoQuirksMode:
192   initial: true
193 usesEncodingDetector:
194   initial: false
195 canvasUsesAcceleratedDrawing:
196   initial: false
197 acceleratedDrawingEnabled:
198   initial: false
199 displayListDrawingEnabled:
200   initial: false
201 acceleratedFiltersEnabled:
202   initial: false
203 useLegacyTextAlignPositionedElementBehavior:
204   initial: false
205 javaScriptRuntimeFlags:
206   type: JSC::RuntimeFlags
207
208 # FIXME: This should really be disabled by default as it makes platforms that don't support the feature download files
209 # they can't use by. Leaving enabled for now to not change existing behavior.
210 downloadableBinaryFontsEnabled:
211   initial: defaultDownloadableBinaryFontsEnabled()
212
213 xssAuditorEnabled:
214   initial: false
215 acceleratedCompositingForFixedPositionEnabled:
216   initial: defaultAcceleratedCompositingForFixedPositionEnabled
217 acceleratedCompositingForOverflowScrollEnabled:
218   initial: false
219 rubberBandingForSubScrollableRegionsEnabled:
220   initial: true
221   conditional: RUBBER_BANDING
222
223 experimentalNotificationsEnabled:
224   initial: false
225 webGLEnabled:
226   initial: false
227 webGLErrorsToConsoleEnabled:
228   initial: true
229 forceSoftwareWebGLRendering:
230   initial: false
231 forceWebGLUsesLowPower:
232   initial: false
233 accelerated2dCanvasEnabled:
234   initial: false
235 loadDeferringEnabled:
236   initial: true
237 webAudioEnabled:
238   initial: false
239 paginateDuringLayoutEnabled:
240   initial: false
241 fullScreenEnabled:
242   initial: false
243   conditional: FULLSCREEN_API
244 asynchronousSpellCheckingEnabled:
245   initial: false
246
247 # This feature requires an implementation of ValidationMessageClient.
248 interactiveFormValidationEnabled:
249   initial: false
250
251 usePreHTML5ParserQuirks:
252   initial: false
253 hyperlinkAuditingEnabled:
254   initial: false
255 crossOriginCheckInGetMatchedCSSRulesDisabled:
256   initial: false
257 forceCompositingMode:
258   initial: false
259 shouldInjectUserScriptsInInitialEmptyDocument:
260   initial: false
261 fixedElementsLayoutRelativeToFrame:
262   initial: false
263 allowDisplayOfInsecureContent:
264   initial: false
265 allowRunningOfInsecureContent:
266   initial: false
267 requiresUserGestureToLoadVideo:
268   initial: defaultRequiresUserGestureToLoadVideo
269 videoPlaybackRequiresUserGesture:
270   initial: defaultVideoPlaybackRequiresUserGesture
271 audioPlaybackRequiresUserGesture:
272   initial: defaultAudioPlaybackRequiresUserGesture
273 mainContentUserGestureOverrideEnabled:
274   initial: false
275 mediaUserGestureInheritsFromDocument:
276   initial: false
277 allowsInlineMediaPlayback:
278   initial: defaultAllowsInlineMediaPlayback
279 allowsInlineMediaPlaybackAfterFullscreen:
280   initial: true
281 inlineMediaPlaybackRequiresPlaysInlineAttribute:
282   initial: defaultInlineMediaPlaybackRequiresPlaysInlineAttribute
283 allowsPictureInPictureMediaPlayback:
284   initial: defaultAllowsPictureInPictureMediaPlayback
285 mediaControlsScaleWithPageZoom:
286   initial: defaultMediaControlsScaleWithPageZoom
287 invisibleAutoplayNotPermitted:
288   initial: false
289 passwordEchoEnabled:
290   initial: false
291 suppressesIncrementalRendering:
292   initial: false
293 incrementalRenderingSuppressionTimeoutInSeconds:
294   type: double
295   initial: defaultIncrementalRenderingSuppressionTimeoutInSeconds
296 backspaceKeyNavigationEnabled:
297   initial: true
298 shouldDisplaySubtitles:
299   initial: false
300   conditional: VIDEO_TRACK
301 shouldDisplayCaptions:
302   initial: false
303   conditional: VIDEO_TRACK
304 shouldDisplayTextDescriptions:
305   initial: false
306   conditional: VIDEO_TRACK
307 scrollingCoordinatorEnabled:
308   initial: false
309 scrollingTreeIncludesFrames:
310   initial: defaultScrollingTreeIncludesFrames
311 scrollAnimatorEnabled:
312   initial: true
313   conditional: SMOOTH_SCROLLING
314 forceUpdateScrollbarsOnMainThreadForPerformanceTesting:
315   initial: false
316 notificationsEnabled:
317   initial: true
318
319 # Some apps needs isLoadingInAPISense to account for active subresource loaders.
320 needsIsLoadingInAPISenseQuirk:
321   initial: false
322
323 shouldRespectImageOrientation:
324   initial: defaultShouldRespectImageOrientation
325 imageSubsamplingEnabled:
326   initial: defaultImageSubsamplingEnabled
327 wantsBalancedSetDefersLoadingBehavior:
328   initial: false
329 requestAnimationFrameEnabled:
330   initial: true
331
332 cookieEnabled:
333   initial: true
334 mediaEnabled:
335   initial: defaultMediaEnabled
336 DOMPasteAllowed:
337   initial: false
338
339 # When enabled, window.blur() does not change focus, and
340 # window.focus() only changes focus when invoked from the context that
341 # created the window.
342 windowFocusRestricted:
343   initial: true
344
345 diagnosticLoggingEnabled:
346   initial: false
347 delegatesPageScaling:
348   initial: false
349 plugInSnapshottingEnabled:
350   initial: false
351 snapshotAllPlugIns:
352   initial: false
353 autostartOriginPlugInSnapshottingEnabled:
354   initial: true
355 primaryPlugInSnapshotDetectionEnabled:
356   initial: true
357 maximumPlugInSnapshotAttempts:
358   type: unsigned
359   initial: 20
360 frameFlattening:
361   type: FrameFlattening
362   initial: FrameFlattening::Disabled
363   onChange: setNeedsRelayoutAllFrames
364 asyncFrameScrollingEnabled:
365   initial: false
366   onChange: setNeedsRelayoutAllFrames
367
368 webSecurityEnabled:
369   initial: true
370 spatialNavigationEnabled:
371   initial: false
372
373 autoscrollForDragAndDropEnabled:
374   initial: false
375
376 unifiedTextCheckerEnabled:
377   initial: defaultUnifiedTextCheckerEnabled
378
379 logsPageMessagesToSystemConsoleEnabled:
380   initial: false
381
382 backForwardCacheExpirationInterval:
383   type: double
384   initial: 1800
385
386 # Some apps could have a default video poster if it is not set.
387 defaultVideoPosterURL:
388   type: String
389
390 smartInsertDeleteEnabled:
391   initial: defaultSmartInsertDeleteEnabled
392 selectTrailingWhitespaceEnabled:
393   initial: defaultSelectTrailingWhitespaceEnabled
394
395 useLegacyBackgroundSizeShorthandBehavior:
396   initial: false
397 fixedBackgroundsPaintRelativeToDocument:
398   initial: defaultFixedBackgroundsPaintRelativeToDocument
399
400 textAutosizingEnabled:
401   initial: defaultTextAutosizingEnabled()
402   onChange: setNeedsRecalcStyleInAllFrames
403   conditional: TEXT_AUTOSIZING
404 textAutosizingWindowSizeOverride:
405   type: IntSize
406   onChange: setNeedsRecalcStyleInAllFrames
407   conditional: TEXT_AUTOSIZING
408 minimumZoomFontSize:
409   type: float
410   initial: defaultMinimumZoomFontSize()
411   conditional: TEXT_AUTOSIZING
412
413 subpixelAntialiasedLayerTextEnabled:
414   initial: false
415   onChange: setNeedsRecalcStyleInAllFrames
416 simpleLineLayoutEnabled:
417   initial: true
418   onChange: setNeedsRecalcStyleInAllFrames
419 simpleLineLayoutDebugBordersEnabled:
420   initial: false
421   onChange: setNeedsRecalcStyleInAllFrames
422
423 subpixelCSSOMElementMetricsEnabled:
424   initial: false
425
426 useGiantTiles:
427   initial: false
428
429 mediaSourceEnabled:
430   initial: true
431   conditional: MEDIA_SOURCE
432
433 sourceBufferChangeTypeEnabled:
434   initial: true
435   conditional: MEDIA_SOURCE
436
437 # FIXME: Rename to allowMultiElementImplicitFormSubmission once we upstream the iOS changes to WebView.mm.
438 allowMultiElementImplicitSubmission:
439   initial: false
440
441 allowsAirPlayForMediaPlayback:
442   initial: true
443   conditional: WIRELESS_PLAYBACK_TARGET
444
445 shouldConvertPositionStyleOnCopy:
446   initial: false
447
448 maxParseDuration:
449   type: double
450   initial: -1
451 standalone:
452   initial: false
453 telephoneNumberParsingEnabled:
454   initial: false
455 mediaDataLoadsAutomatically:
456   initial: defaultMediaDataLoadsAutomatically
457 alwaysUseAcceleratedOverflowScroll:
458   initial: false
459 imageControlsEnabled:
460   initial: false
461   conditional: SERVICE_CONTROLS
462
463 enableInheritURIQueryComponent:
464   initial: false
465
466 aggressiveTileRetentionEnabled:
467   initial: false
468 temporaryTileCohortRetentionEnabled:
469   initial: true
470
471 useImageDocumentForSubframePDF:
472   initial: false
473 dataDetectorTypes:
474   type: DataDetectorTypes
475   initial: DataDetectorTypeNone
476   conditional: DATA_DETECTION
477
478 # Allow SourceBuffers to store up to 304MB each, enough for approximately five minutes
479 # of 1080p video and stereo audio.
480 maximumSourceBufferSize:
481   type: int
482   initial: 318767104
483   conditional: MEDIA_SOURCE
484
485 serviceControlsEnabled:
486   initial: false
487   conditional: SERVICE_CONTROLS
488
489 appleMailPaginationQuirkEnabled:
490   initial: false
491
492 deferredCSSParserEnabled:
493   initial: false
494
495 repaintOutsideLayoutEnabled:
496   initial: false
497
498 httpEquivEnabled:
499   initial: true
500
501 # Some ports (e.g. iOS) might choose to display attachments inline, regardless of whether the response includes the
502 # HTTP header "Content-Disposition: attachment". This setting enables a sandbox around these attachments. The sandbox
503 # enforces all frame sandbox flags (see enum SandboxFlag in SecurityContext.h), and also disables <meta http-equiv>
504 # processing and subframe loading.
505 contentDispositionAttachmentSandboxEnabled:
506   initial: false
507
508 userInterfaceDirectionPolicy:
509   type: UserInterfaceDirectionPolicy
510   initial: UserInterfaceDirectionPolicy::Content
511 systemLayoutDirection:
512   type: TextDirection
513   initial: TextDirection::LTR
514
515 allowContentSecurityPolicySourceStarToMatchAnyProtocol:
516   initial: false
517
518 selectionPaintingWithoutSelectionGapsEnabled:
519   initial: false
520
521 shouldConvertInvalidURLsToBlank:
522   initial: true
523
524 springTimingFunctionEnabled:
525   initial: false
526
527 conicGradientsEnabled:
528   initial: defaultConicGradient
529
530 colorFilterEnabled:
531   initial: false
532   onChange: setNeedsRecalcStyleInAllFrames
533
534 punchOutWhiteBackgroundsInDarkMode:
535   initial: false
536   onChange: setNeedsRecalcStyleInAllFrames
537
538 treatIPAddressAsDomain:
539   initial: false
540
541 mediaPreloadingEnabled:
542   initial: false
543
544 layoutViewportHeightExpansionFactor:
545   type: double
546   initial: 0
547   onChange: setNeedsRecalcStyleInAllFrames
548
549 # Runtime-enabled features
550 visualViewportEnabled:
551   initial: false
552   onChange: setNeedsRecalcStyleInAllFrames
553
554 visualViewportAPIEnabled:
555   initial: false
556
557 CSSOMViewScrollingAPIEnabled:
558   initial: false
559
560 inputEventsEnabled:
561   initial: true
562
563 quickTimePluginReplacementEnabled:
564   initial: defaultQuickTimePluginReplacementEnabled
565 youTubeFlashPluginReplacementEnabled:
566   initial: defaultYouTubeFlashPluginReplacementEnabled
567
568 forcedColorsAreInvertedAccessibilityValue:
569   type: ForcedAccessibilityValue
570   initial: defaultForcedColorsAreInvertedAccessibilityValue
571 forcedDisplayIsMonochromeAccessibilityValue:
572   type: ForcedAccessibilityValue
573   initial: defaultForcedDisplayIsMonochromeAccessibilityValue
574 forcedPrefersReducedMotionAccessibilityValue:
575   type: ForcedAccessibilityValue
576   initial: defaultForcedPrefersReducedMotionAccessibilityValue
577
578 largeImageAsyncDecodingEnabled:
579   initial: true
580 animatedImageAsyncDecodingEnabled:
581   initial: true
582 webkitImageReadyEventEnabled:
583   initial: false
584
585 shouldSuppressTextInputFromEditingDuringProvisionalNavigation:
586   initial: false
587
588 langAttributeAwareFormControlUIEnabled:
589   initial: false
590
591 subresourceIntegrityEnabled:
592   initial: true
593
594 linkPreconnectEnabled:
595   initial: false
596
597 beaconAPIEnabled:
598   initial: false
599
600 geolocationFloorLevelEnabled:
601   initial: true
602
603 constantPropertiesEnabled:
604   initial: false
605
606 viewportFitEnabled:
607   initial: false
608
609 allowMediaContentTypesRequiringHardwareSupportAsFallback:
610   initial: false
611
612 storageAccessAPIEnabled:
613   initial: true
614
615 timeWithoutMouseMovementBeforeHidingControls:
616   type: Seconds
617   initial: 3_s
618
619 fontFallbackPrefersPictographs:
620   initial: false
621   onChange: setNeedsRecalcStyleInAllFrames
622
623 fontLoadTimingOverride:
624   type: FontLoadTimingOverride
625   initial: FontLoadTimingOverride::None
626 shouldIgnoreFontLoadCompletions:
627   initial: false
628
629 paymentRequestEnabled:
630   initial: false
631   conditional: PAYMENT_REQUEST
632 applePayEnabled:
633   initial: false
634   conditional: APPLE_PAY
635 applePayCapabilityDisclosureAllowed:
636   initial: true
637   conditional: APPLE_PAY
638
639 javaEnabled:
640   initial: false
641   getter: isJavaEnabled
642 javaEnabledForLocalFiles:
643   initial: true
644   getter: isJavaEnabledForLocalFiles
645
646 # Unlike the imagesEnabled setting, this only suppresses the network load of
647 # the image URL. A cached image will still be rendered if requested.
648 loadsImagesAutomatically:
649   initial: false
650   onChange: imagesEnabledChanged
651 imagesEnabled:
652   initial: true
653   getter: areImagesEnabled
654   onChange: imagesEnabledChanged
655 scriptEnabled:
656   initial: false
657   getter: isScriptEnabled
658   onChange: scriptEnabledChanged
659 pluginsEnabled:
660   initial: false
661   getter: arePluginsEnabled
662   onChange: pluginsEnabledChanged
663
664 usesPageCache:
665   initial: false
666   onChange: usesPageCacheChanged
667
668 dnsPrefetchingEnabled:
669   initial: false
670   onChange: dnsPrefetchingEnabledChanged
671
672 backgroundShouldExtendBeyondPage:
673   initial: false
674   onChange: backgroundShouldExtendBeyondPageChanged
675
676 scrollingPerformanceLoggingEnabled:
677   initial: false
678   onChange: scrollingPerformanceLoggingEnabledChanged
679
680 hiddenPageDOMTimerThrottlingEnabled:
681   initial: false
682   onChange: hiddenPageDOMTimerThrottlingStateChanged
683 hiddenPageDOMTimerThrottlingAutoIncreases:
684   initial: false
685   onChange: hiddenPageDOMTimerThrottlingStateChanged
686 hiddenPageCSSAnimationSuspensionEnabled:
687   initial: false
688   onChange: hiddenPageCSSAnimationSuspensionEnabledChanged
689
690 storageBlockingPolicy:
691   type: SecurityOrigin::StorageBlockingPolicy
692   initial: SecurityOrigin::AllowAllStorage
693   onChange: storageBlockingPolicyChanged
694
695 shouldAllowUserInstalledFonts:
696   initial: true
697   onChange: setNeedsRecalcStyleInAllFrames
698
699 # Only set by Layout Tests.
700 mediaTypeOverride:
701   type: String
702   initial: '"screen"'
703   onChange: mediaTypeOverrideChanged
704
705
706 fontRenderingMode:
707   type: FontRenderingMode
708   initial: FontRenderingMode::Normal
709
710 preferMIMETypeForImages:
711   initial: false
712
713 forcePendingWebGLPolicy:
714   initial: false
715   getter: isForcePendingWebGLPolicy
716
717 mediaKeysStorageDirectory:
718   type: String
719
720 mediaDeviceIdentifierStorageDirectory:
721   type: String
722   conditional: MEDIA_STREAM
723
724 # FIXME: This quirk is needed because of Radar 4674537 and 5211271. We need to phase it out once Adobe
725 # can fix the bug from their end.
726 needsAdobeFrameReloadingQuirk:
727   initial: false
728   getter: needsAcrobatFrameReloadingQuirk
729
730 passiveTouchListenersAsDefaultOnDocument:
731   initial: true
732
733 touchEventEmulationEnabled:
734   initial: false
735   getter: isTouchEventEmulationEnabled
736   conditional: TOUCH_EVENTS
737
738 shouldEnableTextAutosizingBoost:
739   type: bool
740   initial: false
741   conditional: TEXT_AUTOSIZING
742   onChange: shouldEnableTextAutosizingBoostChanged
743
744 mediaCapabilitiesEnabled:
745   initial: false
746
747 resourceLoadStatisticsDebugMode:
748   initial: false
749
750 clientCoordinatesRelativeToLayoutViewport:
751   initial: false
752   onChange: setNeedsRecalcStyleInAllFrames
753
754 crossOriginWindowPolicySupportEnabled:
755   initial: false
756
757 accessibilityEventsEnabled:
758   initial: true
759   conditional: ACCESSIBILITY_EVENTS
760
761 incompleteImageBorderEnabled:
762   initial: false
763
764 shouldDeferAsynchronousScriptsUntilAfterDocumentLoad:
765   initial: false