bug 441235, shift-tab gets stuck in the comments field in the Mac crashreporter client. r=ted

toolkit/crashreporter/client/crashreporter_osx.h

@@ -132,6 +132,7 @@
 - (BOOL)resignFirstResponder;  
 - (void)setPlaceholder:(NSString*)placeholder;
 - (void)insertTab:(id)sender;
+- (void)insertBacktab:(id)sender;
 - (void)setEnabled:(BOOL)enabled;
 - (void)dealloc;
 

toolkit/crashreporter/client/crashreporter_osx.mm

@@ -677,6 +677,11 @@ static bool RestartApplication()
   [[self window] selectNextKeyView:sender];
 }
 
+- (void)insertBacktab:(id)sender
+{
+  [[self window] selectPreviousKeyView:sender];
+}
+
 - (void)setEnabled:(BOOL)enabled
 {
   [self setSelectable:enabled];