Inline default false setting for unifiedTextCheckerEnabled 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 146 matching lines @@
 
 # Special keyboard navigation mode intented for platforms with no
 # proper mouse or touch support, such as a TV controller with a remote.
 spatialNavigationEnabled initial=false
 
 # This setting adds a means to enable/disable touch initiated drag & drop. If
 # enabled, the user can initiate drag using long press.
 # crbug.com/304894 tracks removal once it's been enabled on all platforms.
 touchDragDropEnabled initial=false
 
-unifiedTextCheckerEnabled initial=defaultUnifiedTextCheckerEnabled
+unifiedTextCheckerEnabled initial=false
 
 # Some apps could have a default video poster if it is not set.
 defaultVideoPosterURL type=String
 
 smartInsertDeleteEnabled initial=false
 selectTrailingWhitespaceEnabled initial=defaultSelectTrailingWhitespaceEnabled
 
 selectionIncludesAltImageText initial=false
 
 selectionStrategy type=SelectionStrategy, initial=SelectionStrategy::Character
@@ skipping 190 matching lines @@
 # Overall rationale and details here: https://docs.google.com/document/d/1bCDuq9H1ih9iNjgzyAL0gpwNFiEP4TZS-YLRp_RuMlc/edit?usp=sharing
 fetchDeferLateScripts initial=false
 fetchIncreaseFontPriority initial=false
 fetchIncreaseAsyncScriptPriority initial=false
 # Increases the priorities for CSS, Scripts, Fonts and Images all by one level
 # and parser-blocking scripts and visible images by 2.
 # This is used in conjunction with logic on the Chrome side to raise the threshold
 # of "layout-blocking" resources and provide a boost to resources that are needed
 # as soon as possible for something currently on the screen.
 fetchIncreasePriorities initial=false