Cherry-pick 0d08a5fd7147. rdar://133862081

    Use LazyNeverDestroyed in `static TextCheckerState& mutableState()`
    https://bugs.webkit.org/show_bug.cgi?id=280209
    rdar://133862081

    Reviewed by Alex Christensen.

    Speculative fix. Crash reports indicate that mutableState() can be corrupted such that it contains
    non-bool values. Use LazyNeverDestroyed + dispatch_once to avoid issues when statically initializing this
    object from multiple threads.

    * Source/WebKit/UIProcess/mac/TextCheckerMac.mm:
    (WebKit::mutableState):

    Canonical link: https://commits.webkit.org/284120@main

Canonical link: https://commits.webkit.org/280938.373@safari-7619-branch

Source/WebKit/UIProcess/mac/TextCheckerMac.mm

diff --git a/Source/WebKit/UIProcess/mac/TextCheckerMac.mm b/Source/WebKit/UIProcess/mac/TextCheckerMac.mm
index cb368a8..1cb4d59 100644
--- a/Source/WebKit/UIProcess/mac/TextCheckerMac.mm
+++ b/Source/WebKit/UIProcess/mac/TextCheckerMac.mm
@@ -97,7 +97,9 @@
 
 static TextCheckerState& mutableState()
 {
-    static NeverDestroyed state = [] {
+    static LazyNeverDestroyed<TextCheckerState> state;
+    static std::once_flag onceFlag;
+    std::call_once(onceFlag, [] {
         TextCheckerState initialState;
         initialState.isContinuousSpellCheckingEnabled = [[NSUserDefaults standardUserDefaults] boolForKey:WebContinuousSpellCheckingEnabled] && TextChecker::isContinuousSpellCheckingAllowed();
         initialState.isGrammarCheckingEnabled = shouldGrammarCheckingBeEnabled();
@@ -106,8 +108,8 @@
         initialState.isAutomaticQuoteSubstitutionEnabled = shouldAutomaticQuoteSubstitutionBeEnabled();
         initialState.isAutomaticDashSubstitutionEnabled = shouldAutomaticDashSubstitutionBeEnabled();
         initialState.isAutomaticLinkDetectionEnabled = [[NSUserDefaults standardUserDefaults] boolForKey:WebAutomaticLinkDetectionEnabled];
-        return initialState;
-    }();
+        state.construct(WTFMove(initialState));
+    });
     return state;
 }