Fix "unreachable code" warnings (MSVC warning 4702) in chrome/browser/.

chrome/browser/extensions/api/media_galleries_private/gallery_watch_state_tracker.cc

 // 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.
 
 // GalleryWatchStateTracker implementation.
 
 #include "chrome/browser/extensions/api/media_galleries_private/gallery_watch_state_tracker.h"
 
 #include "base/bind.h"
 #include "base/files/file_path.h"
@@ skipping 85 matching lines @@
 // static
 GalleryWatchStateTracker* GalleryWatchStateTracker::GetForProfile(
     Profile* profile) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
 #if defined(OS_WIN)
   // Gallery watch operation is supported only on windows.
   // Please refer to crbug.com/144491 for more details.
   DCHECK(profile);
   MediaGalleriesPrivateAPI* private_api =
       MediaGalleriesPrivateAPI::Get(profile);
-  if (!private_api)
-    return NULL;  // In unit tests, we don't have a MediaGalleriesPrivateAPI.
-  return private_api->GetGalleryWatchStateTracker();
+  // In unit tests, we don't have a MediaGalleriesPrivateAPI.
+  if (private_api)
+    return private_api->GetGalleryWatchStateTracker();
 #endif
   return NULL;
 }
 
 void GalleryWatchStateTracker::OnPermissionAdded(
     MediaGalleriesPreferences* preferences,
     const std::string& extension_id,
     MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   // Granted gallery permission.
@@ skipping 227 matching lines @@
     const std::string& extension_id,
     MediaGalleryPrefId gallery_id) {
   DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
   if (HasGalleryWatchInfo(extension_id, gallery_id, true))
     return false;
   watched_extensions_map_[extension_id][gallery_id] = true;
   return true;
 }
 
 }  // namespace extensions