Remove useless check before delete

It's okay to pass nullptr to delete, as by default it will call free()
that will check for NULL, so there's no need for redundant checks.

Bug: none
Change-Id: I450ee684f78d0cf3f1394d18de788df67f6435c9
Reviewed-on: https://chromium-review.googlesource.com/988960Reviewed-by: Scott Violet <sky@chromium.org>
Commit-Queue: Andre Goddard Rosa <andre.rosa@lge.com>
Cr-Commit-Position: refs/heads/master@{#547556}

ui/base/resource/resource_bundle.cc

@@ -214,10 +214,8 @@ void ResourceBundle::InitSharedInstanceWithPakPath(const base::FilePath& path) {
 
 // static
 void ResourceBundle::CleanupSharedInstance() {
-  if (g_shared_instance_) {
-    delete g_shared_instance_;
-    g_shared_instance_ = NULL;
-  }
+  delete g_shared_instance_;
+  g_shared_instance_ = NULL;
 }
 
 // static