[Mac] Keep download buttons alive while processing events.

chrome/browser/ui/cocoa/draggable_button.mm

Index: chrome/browser/ui/cocoa/draggable_button.mm
diff --git a/chrome/browser/ui/cocoa/draggable_button.mm b/chrome/browser/ui/cocoa/draggable_button.mm
index 91e8ef266f59d6ac9ac49819564edc756dea1816..1eb7d7dd7aa8c9e9773b98f4f7721976ce2589e7 100644
--- a/chrome/browser/ui/cocoa/draggable_button.mm
+++ b/chrome/browser/ui/cocoa/draggable_button.mm
@@ -36,6 +36,11 @@
 }
 
 - (void)mouseDown:(NSEvent*)theEvent {
+  // The impl spins an event loop to distinguish clicks from drags,
+  // which could result in our destruction.  Wire ourselves down for
+  // the duration.
+  scoped_nsobject<DraggableButton> keepAlive([self retain]);

[Robert Sesek, 2011/08/23 22:56:48]

Would it be better to do this in the impl?

[Scott Hess - ex-Googler, 2011/08/23 23:04:37]

How?

[Robert Sesek, 2011/08/23 23:10:13]

Retain button_ in the Impl in the loop?

+
   if ([draggableButtonImpl_ mouseDownImpl:theEvent] ==
           kDraggableButtonMixinCallSuper) {
     [super mouseDown:theEvent];