Fix crashes in ExtensionService

chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.mm

 // 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.
 
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_controller.h"
 
 #include "base/mac/mac_util.h"
 #include "base/metrics/histogram.h"
 #include "base/sys_string_conversions.h"
 #include "chrome/browser/bookmarks/bookmark_editor.h"
@@ skipping 102 matching lines @@
 namespace {
 
 // Overlap (in pixels) between the toolbar and the bookmark bar (when showing in
 // normal mode).
 const CGFloat kBookmarkBarOverlap = 3.0;
 
 // Duration of the bookmark bar animations.
 const NSTimeInterval kBookmarkBarAnimationDuration = 0.12;
 
 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
 
 @interface BookmarkBarController(Private)
@@ skipping 2369 matching lines @@
 // to minimize touching the object passed in (likely a mock).
 - (void)setButtonContextMenu:(id)menu {
   buttonContextMenu_ = menu;
 }
 
 - (void)setIgnoreAnimations:(BOOL)ignore {
   ignoreAnimations_ = ignore;
 }
 
 @end