Remove the acceleratedCompositingForCanvas setting.

Source/core/frame/Settings.in

 # Defines properties which are available on the Settings object.
 #
 # Please think carefully before adding a new Setting.  Some questions to
 # consider are:
 # - Should this be a RuntimeEnabledFeature instead? Settings are for things
 #   which we support either values of at runtime.  Features are set at renderer
 #   process startup and are never changed. Features also tend to be set to a
 #   value based on the platform or the stability of the code in question, where
 #   as settings both codepaths need to be stable.
 # - How will you ensure test coverage of all relevant values of your setting?
@@ skipping 75 matching lines @@
 
 # FIXME: This should really be disabled by default as it makes platforms that
 # don't support the feature download files they can't use by.
 # Leaving enabled for now to not change existing behavior.
 downloadableBinaryFontsEnabled initial=true
 
 xssAuditorEnabled initial=false
 unsafePluginPastingEnabled initial=true
 treatIPAddressAsDomain initial=false
 
-acceleratedCompositingForCanvasEnabled initial=true, invalidate=AcceleratedCompositing
 acceleratedCompositingForFixedPositionEnabled initial=false, invalidate=AcceleratedCompositing
 acceleratedCompositingForOverflowScrollEnabled initial=false, invalidate=AcceleratedCompositing
 acceleratedCompositingForFixedRootBackgroundEnabled initial=false
 compositedScrollingForFramesEnabled initial=false, invalidate=AcceleratedCompositing
 
 # 3D canvas (WebGL) support.
 webGLEnabled initial=false
 
 webGLErrorsToConsoleEnabled initial=true
 accelerated2dCanvasEnabled initial=false
@@ skipping 179 matching lines @@
 # the Android WebView framework supports fullscreen for non-media elements
 # (crbug.com/398485).
 # This value is set to false if the platform does not support fullscreen
 # for non-media elements. When set to true all the requests to enter fullscreen
 # on non-media elements will return an error.
 disallowFullscreenForNonMediaElements initial=false
 
 # V8 supports different types of caching. Used by V8 bindings.
 v8CacheOptions type=V8CacheOptions, initial=V8CacheOptionsOff