[ios/web] Don't expose internal restore session URLs.

A followup to http://crrev.com/c/1673566.  Strip our restore and placeholder
information out of the URL returned by GetCurrentURL().

Change-Id: I86075a81099fca5bc74f6fabcb44c4faad216f9f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1677804
Auto-Submit: Justin Cohen <justincohen@chromium.org>
Reviewed-by: Eugene But <eugenebut@chromium.org>
Commit-Queue: Justin Cohen <justincohen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672575}

ios/web/navigation/wk_based_navigation_manager_impl.mm

@@ -781,6 +781,17 @@ WKBasedNavigationManagerImpl::GetLastCommittedItemInCurrentOrRestoredSession()
       last_committed_web_view_item_->SetUntrusted();
     }
     last_committed_web_view_item_->SetURL(document_url);
+    // Don't expose internal restore session URL's.
+    GURL virtual_url;
+    if (wk_navigation_util::IsRestoreSessionUrl(document_url) &&
+        wk_navigation_util::ExtractTargetURL(document_url, &virtual_url)) {
+      if (wk_navigation_util::IsPlaceholderUrl(virtual_url)) {
+        last_committed_web_view_item_->SetVirtualURL(
+            wk_navigation_util::ExtractUrlFromPlaceholderUrl(virtual_url));
+      } else {
+        last_committed_web_view_item_->SetVirtualURL(virtual_url);
+      }
+    }
     last_committed_web_view_item_->SetTimestamp(
         time_smoother_.GetSmoothedTime(base::Time::Now()));
     return last_committed_web_view_item_.get();