Fix hang in open/save dialogs on Mojave

Author: dstillman

mac/mozilla-52.patch

@@ -17,6 +17,72 @@ diff --git a/browser/app/nsBrowserApp.cpp b/browser/app/nsBrowserApp.cpp
    if (appDataFile && *appDataFile) {
      rv = XRE_GetFileFromPath(appDataFile, getter_AddRefs(appini));
      if (NS_FAILED(rv)) {
+diff --git a/widget/cocoa/nsChildView.mm b/widget/cocoa/nsChildView.mm
+--- a/widget/cocoa/nsChildView.mm
++++ b/widget/cocoa/nsChildView.mm
+@@ -428,13 +428,6 @@ nsChildView::Create(nsIWidget* aParent,
+   if (!gChildViewMethodsSwizzled) {
+     nsToolkit::SwizzleMethods([NSView class], @selector(mouseDownCanMoveWindow),
+                               @selector(nsChildView_NSView_mouseDownCanMoveWindow));
+-#ifdef __LP64__
+-    nsToolkit::SwizzleMethods([NSEvent class], @selector(addLocalMonitorForEventsMatchingMask:handler:),
+-                              @selector(nsChildView_NSEvent_addLocalMonitorForEventsMatchingMask:handler:),
+-                              true);
+-    nsToolkit::SwizzleMethods([NSEvent class], @selector(removeMonitor:),
+-                              @selector(nsChildView_NSEvent_removeMonitor:), true);
+-#endif
+     gChildViewMethodsSwizzled = true;
+   }
+ 
+@@ -6533,48 +6526,3 @@ static const CGEventField kCGWindowNumbe
+ }
+ 
+ @end
+-
+-#ifdef __LP64__
+-// When using blocks, at least on OS X 10.7, the OS sometimes calls
+-// +[NSEvent removeMonitor:] more than once on a single event monitor, which
+-// causes crashes.  See bug 678607.  We hook these methods to work around
+-// the problem.
+-@interface NSEvent (MethodSwizzling)
+-+ (id)nsChildView_NSEvent_addLocalMonitorForEventsMatchingMask:(unsigned long long)mask handler:(id)block;
+-+ (void)nsChildView_NSEvent_removeMonitor:(id)eventMonitor;
+-@end
+-
+-// This is a local copy of the AppKit frameworks sEventObservers hashtable.
+-// It only stores "local monitors".  We use it to ensure that +[NSEvent
+-// removeMonitor:] is never called more than once on the same local monitor.
+-static NSHashTable *sLocalEventObservers = nil;
+-
+-@implementation NSEvent (MethodSwizzling)
+-
+-+ (id)nsChildView_NSEvent_addLocalMonitorForEventsMatchingMask:(unsigned long long)mask handler:(id)block
+-{
+-  if (!sLocalEventObservers) {
+-    sLocalEventObservers = [[NSHashTable hashTableWithOptions:
+-      NSHashTableStrongMemory | NSHashTableObjectPointerPersonality] retain];
+-  }
+-  id retval =
+-    [self nsChildView_NSEvent_addLocalMonitorForEventsMatchingMask:mask handler:block];
+-  if (sLocalEventObservers && retval && ![sLocalEventObservers containsObject:retval]) {
+-    [sLocalEventObservers addObject:retval];
+-  }
+-  return retval;
+-}
+-
+-+ (void)nsChildView_NSEvent_removeMonitor:(id)eventMonitor
+-{
+-  if (sLocalEventObservers && [eventMonitor isKindOfClass: ::NSClassFromString(@"_NSLocalEventObserver")]) {
+-    if (![sLocalEventObservers containsObject:eventMonitor]) {
+-      return;
+-    }
+-    [sLocalEventObservers removeObject:eventMonitor];
+-  }
+-  [self nsChildView_NSEvent_removeMonitor:eventMonitor];
+-}
+-
+-@end
+-#endif // #ifdef __LP64__
 diff --git a/widget/cocoa/nsCocoaFeatures.h b/widget/cocoa/nsCocoaFeatures.h
 --- a/widget/cocoa/nsCocoaFeatures.h
 +++ b/widget/cocoa/nsCocoaFeatures.h