Check host_ is not NULL in isRToL.

remoting/host/disconnect_window_mac.mm

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <Cocoa/Cocoa.h>
 
 #import "remoting/host/disconnect_window_mac.h"
 
 #include "base/compiler_specific.h"
 #include "base/string_util.h"
@@ skipping 78 matching lines @@
 }
 
 - (IBAction)stopSharing:(id)sender {
   if (self.host) {
     self.host->Shutdown(base::Closure());
     self.host = NULL;
   }
 }
 
 - (BOOL)isRToL {
-  return host_->ui_strings().direction == remoting::UiStrings::RTL;
+  if (host_) {
+    return host_->ui_strings().direction == remoting::UiStrings::RTL;
+  } else {
+    return false;
+  }
 }
 
 - (void)close {
   self.host = NULL;
   [super close];
 }
 
 - (void)windowDidLoad {
   string16 text = ReplaceStringPlaceholders(
       host_->ui_strings().disconnect_message,
@@ skipping 175 matching lines @@
   path = [NSBezierPath bezierPath];
   [path moveToPoint:top];
   [path lineToPoint:bottom];
   [light setStroke];
   [path stroke];
 
   [context setShouldAntialias:alias];
 }
 
 @end