Manually invalidate the FontCache before clearing ThreadGlobalData.

https://bugs.webkit.org/show_bug.cgi?id=248502

Reviewed by Cameron McCormack.

Destructing the FontCache can recurse back into the ThreadGlobalData getter (to remove cached entries), so
we want to manually clear the FontCache before clearing the ThreadGlobalData pointer.

This also moves m_destroyed to earlier in the class, so it's guaranteed to be destructed after m_fontCache.

* Source/WebCore/platform/ThreadGlobalData.cpp:
(WebCore::ThreadGlobalData::destroy):
* Source/WebCore/platform/ThreadGlobalData.h:
* Source/WebCore/platform/graphics/FontCache.h:

Canonical link: https://commits.webkit.org/257160@main

Source/WebCore/platform/ThreadGlobalData.cpp

@@ -51,6 +51,9 @@ ThreadGlobalData::~ThreadGlobalData() = default;
 
 void ThreadGlobalData::destroy()
 {
+    if (m_fontCache)
+        m_fontCache->invalidate();
+    m_fontCache = nullptr;
     m_destroyed = true;
 }
 

Source/WebCore/platform/ThreadGlobalData.h

@@ -106,6 +106,8 @@ class ThreadGlobalData : public PAL::ThreadGlobalData {
     FontCache* fontCacheIfNotDestroyed() { return m_destroyed ? nullptr : &fontCache(); }
 
 private:
+    bool m_destroyed { false };
+
     WEBCORE_EXPORT void initializeCachedResourceRequestInitiators();
     WEBCORE_EXPORT void initializeEventNames();
     WEBCORE_EXPORT void initializeQualifiedNameCache();
@@ -125,7 +127,6 @@ class ThreadGlobalData : public PAL::ThreadGlobalData {
 #endif
 
     bool m_isInRemoveAllEventListeners { false };
-    bool m_destroyed { false };
 
     WEBCORE_EXPORT friend ThreadGlobalData& threadGlobalData();
 };

Source/WebCore/platform/graphics/FontCache.h

@@ -195,8 +195,9 @@ class FontCache {
     static bool configurePatternForFontDescription(FcPattern*, const FontDescription&);
 #endif
 
-private:
     void invalidate();
+
+private:
     void releaseNoncriticalMemory();
     void platformReleaseNoncriticalMemory();
     void platformInvalidate();