Remove the redundant check for document nullptr in NetInfo API

Change-Id: I014ee6f6dfd465f6ea855c7ff8f55acc0d87d629
Reviewed-on: https://chromium-review.googlesource.com/1091634
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Kentaro Hara <haraken@chromium.org>
Cr-Commit-Position: refs/heads/master@{#565492}

third_party/blink/renderer/modules/netinfo/network_information.cc

@@ -26,8 +26,8 @@ Settings* GetSettings(ExecutionContext* execution_context) {
     return nullptr;
 
   Document* document = ToDocument(execution_context);
-  if (!document)
-    return nullptr;
+  // |document| is guaranteed to be non-null since |execution_context| is
+  // non-null.
   return document->GetSettings();
 }