Bug 1578075 - Increase stack size of paint threads on macOS Catalina to 2MB. r=jrmuizel

Still getting some crash reports on nightly with a 1MB stack. Let's try one more time
with 2MB just to see if we can eliminate those. If this fails, then we may need to consider
more drastic approaches like disabling OMTP in this case.

Differential Revision: https://phabricator.services.mozilla.com/D47080

--HG--
extra : moz-landing-system : lando

gfx/layers/PaintThread.cpp

@@ -79,7 +79,7 @@ static uint32_t GetPaintThreadStackSize() {
 #else
   // Workaround bug 1578075 by increasing the stack size of paint threads
   if (nsCocoaFeatures::OnCatalinaOrLater()) {
-    static const uint32_t kCatalinaPaintThreadStackSize = 1024 * 1024;
+    static const uint32_t kCatalinaPaintThreadStackSize = 2 * 1024 * 1024;
     static_assert(kCatalinaPaintThreadStackSize >= nsIThreadManager::DEFAULT_STACK_SIZE,
                   "update default stack size of paint "
                   "workers");