Make PreviewsLitePageDecider preconnect with a NetworkIsolationKey.

Also make PreconnectManager::StartPreconnectUrl()'s NetworkIsolationKey
mandatory, as all callers are now passing one in.

Bug: 966896
Change-Id: Id10c410225c5d8248569443381856a3c12d452aa
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1721513
Commit-Queue: Matt Menke <mmenke@chromium.org>
Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Alex Ilin <alexilin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682815}

chrome/browser/predictors/preconnect_manager.h

@@ -152,16 +152,10 @@ class PreconnectManager {
   // |network_isolation_key| specifies the key that network requests for the
   // preconnected URL are expected to use. If a request is issued with a
   // different key, it may not use the preconnected socket.
-  //
-  // TODO(https://crbug.com/966896): Update consumers and make
-  // |network_isolation_key| a mandatory argument. Note that this is a temporary
-  // style guide violation, but keeping this until all consumers correctly fill
-  // the argument reduces the chances of forgetting to update one.
   virtual void StartPreconnectUrl(
       const GURL& url,
       bool allow_credentials,
-      net::NetworkIsolationKey network_isolation_key =
-          net::NetworkIsolationKey());
+      net::NetworkIsolationKey network_isolation_key);
 
   // No additional jobs keyed by the |url| will be queued after this.
   virtual void Stop(const GURL& url);

chrome/browser/previews/previews_lite_page_decider.cc

@@ -41,6 +41,8 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/browser/web_contents_user_data.h"
 #include "net/base/net_errors.h"
+#include "net/base/network_isolation_key.h"
+#include "url/origin.h"
 
 namespace {
 const char kUserNeedsNotification[] =
@@ -92,8 +94,11 @@ void PreconnectToLitePagesServer(content::BrowserContext* browser_context) {
   if (!loading_predictor || !loading_predictor->preconnect_manager())
     return;
 
+  url::Origin previews_origin =
+      url::Origin::Create(previews::params::GetLitePagePreviewsDomainURL());
   loading_predictor->preconnect_manager()->StartPreconnectUrl(
-      previews::params::GetLitePagePreviewsDomainURL(), true);
+      previews::params::GetLitePagePreviewsDomainURL(), true,
+      net::NetworkIsolationKey(previews_origin, previews_origin));
 }
 
 }  // namespace