Fix crashes in ExtensionService

chrome/browser/ui/views/bookmark_bar_view.cc

 // Copyright (c) 2011 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.
 
 #include "chrome/browser/ui/views/bookmark_bar_view.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <vector>
@@ skipping 217 matching lines @@
     return views::MenuButton::OnMousePressed(e);
   }
 
  private:
   BookmarkBarView* owner_;
 
   DISALLOW_COPY_AND_ASSIGN(OverFlowButton);
 };
 
 void RecordAppLaunch(Profile* profile, GURL url) {
-  if (!profile->GetExtensionService()->IsInstalledApp(url))
+  // TODO: the ExtensionService should never be NULL, but in some cases it is,
+  // see bug 73768. After it is resolved, the explicit test can go away.
+  ExtensionService* service = profile->GetExtensionService();
+  if (!service || !service->IsInstalledApp(url))
     return;
 
   UMA_HISTOGRAM_ENUMERATION(extension_misc::kAppLaunchHistogram,
                             extension_misc::APP_LAUNCH_BOOKMARK_BAR,
                             extension_misc::APP_LAUNCH_BUCKET_BOUNDARY);
 }
 
 }  // namespace
 
 // DropInfo -------------------------------------------------------------------
@@ skipping 1511 matching lines @@
   // The tooltip is the only way we have to display text explaining the error
   // to the user.
   sync_error_button->SetTooltipText(
       UTF16ToWide(l10n_util::GetStringUTF16(IDS_SYNC_BOOKMARK_BAR_ERROR_DESC)));
   sync_error_button->SetAccessibleName(
       l10n_util::GetStringUTF16(IDS_ACCNAME_SYNC_ERROR_BUTTON));
   sync_error_button->SetIcon(
       *ResourceBundle::GetSharedInstance().GetBitmapNamed(IDR_WARNING));
   return sync_error_button;
 }