[Mac] Poke KVO for prefs::kDownloadDefaultDirectory when resetting to default values.

chrome/browser/cocoa/preferences_window_controller.mm

 // Copyright (c) 2010 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 "chrome/browser/cocoa/preferences_window_controller.h"
 
 #include <algorithm>
 
 #include "app/l10n_util.h"
 #include "app/l10n_util_mac.h"
@@ skipping 1360 matching lines @@
   }
   else if (*prefName == prefs::kDnsPrefetchingEnabled) {
     [self setDnsPrefetch:dnsPrefetch_.GetValue() ? YES : NO];
   }
   else if (*prefName == prefs::kSafeBrowsingEnabled) {
     [self setSafeBrowsing:safeBrowsing_.GetValue() ? YES : NO];
   }
   else if (*prefName == prefs::kMetricsReportingEnabled) {
     [self setMetricsRecording:metricsRecording_.GetValue() ? YES : NO];
   }
+  else if (*prefName == prefs::kDownloadDefaultDirectory) {
+    // Poke KVO.
+    [self willChangeValueForKey:@"defaultDownloadLocation"];
+    [self didChangeValueForKey:@"defaultDownloadLocation"];
+  }
   else if (*prefName == prefs::kPromptForDownload) {
     [self setAskForSaveLocation:askForSaveLocation_.GetValue() ? YES : NO];
   }
   else if (*prefName == prefs::kEnableTranslate) {
     [self setTranslateEnabled:translateEnabled_.GetValue() ? YES : NO];
   }
   else if (*prefName == prefs::kWebkitTabsToLinks) {
     [self setTabsToLinks:tabsToLinks_.GetValue() ? YES : NO];
   }
   else if (*prefName == prefs::kDownloadExtensionsToOpen) {
@@ skipping 683 matching lines @@
     case OPTIONS_PAGE_ADVANCED:
       return underTheHoodView_;
     case OPTIONS_PAGE_DEFAULT:
     case OPTIONS_PAGE_COUNT:
       LOG(DFATAL) << "Invalid page value " << page;
   }
   return basicsView_;
 }
 
 @end